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| model 2000 multimeter user s manual a greater measure of confidence
warranty keithley instruments, inc. warrants this product to be free from defects in material and workmanship for a period of 3 years from date of shipment. keithley instruments, inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batteries, diskettes, and documentation. during the warranty period, we will, at our option, either repair or replace any product that proves to be defective. to exercise this warranty, write or call your local keithley representative, or contact keithley headquarters in cleveland, ohio. you will be given prompt assistance and return instructions. send the product, transportation prepaid, to the indicated service facility. repairs will be made and the product returned, transportation prepaid. repaired or replaced products are warranted for the balance of the original warranty period, or at least 90 days. limitation of warranty this warranty does not apply to defects resulting from product modi?ation without keithley s express written consent, or misuse of any product or part. this warranty also does not apply to fuses, software, non-rechargeable batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instructions. this warranty is in lieu of all other warranties, expressed or implied, including any implied warranty of merchantability or fitness for a particular use. the remedies provided herein are buyer? sole and exclusive remedies. neither keithley instruments, inc. nor any of its employees shall be liable for any direct, indirect, special, incidental or consequential damages arising out of the use of its instruments and software even if keithley instruments, inc., has been advised in advance of the possibility of such damages. such excluded dam- ages shall include, but are not limited to: costs of removal and installation, losses sustained as the result of injury to any person, or damage to property. keithley instruments, inc. 28775 aurora road ?cleveland, ohio 44139 ?440-248-0400 ?fax: 440-248-6168 1-888-keithley (534-8453) ?www.keithley.com sales of?es: belgium: bergensesteenweg 709 ?b-1600 sint-pieters-leeuw ?02-363 00 40 ?fax: 02/363 00 64 china: yuan chen xin building, room 705 ?12 yumin road, dewai, madian ?beijing 100029 ?8610-6202-2886 ?fax: 8610-6202-2892 finland: tiet?j?ntie 2 ?02130 espoo ?phone: 09-54 75 08 10 ?fax: 09-25 10 51 00 france: 3, all?e des garays ?91127 palaiseau c?dex ?01-64 53 20 20 ?fax: 01-60 11 77 26 germany: landsberger strasse 65 ?82110 germering ?089/84 93 07-40 ?fax: 089/84 93 07-34 great britain: unit 2 commerce park, brunel road ?theale ?berkshire rg7 4ab ?0118 929 7500 ?fax: 0118 929 7519 india: flat 2b, willocrissa ?14, rest house crescent ?bangalore 560 001 ?91-80-509-1320/21 ?fax: 91-80-509-1322 italy: viale san gimignano, 38 ?20146 milano ?02-48 39 16 01 ?fax: 02-48 30 22 74 korea: fl., uri building ?2-14 yangjae-dong ?seocho-gu, seoul 137-130 ?82-2-574-7778 ?fax: 82-2-574-7838 netherlands: postbus 559 ?4200 an gorinchem ?0183-635333 ?fax: 0183-630821 sweden: c/o regus business centre ?frosundaviks all? 15, 4tr ?169 70 solna ?08-509 04 679 ?fax: 08-655 26 10 switzerland: kriesbachstrasse 4 ?8600 d?bendorf ?01-821 94 44 ?fax: 01-820 30 81 taiwan: 1fl., 85 po ai street ?hsinchu, taiwan, r.o.c. ?886-3-572-9077?fax: 886-3-572-9031 ?copyright 2001 keithley instruments, inc. printed in the u.s.a. 11/01 model 2000 multimeter user s manual ?994, keithley instruments, inc. all rights reserved. cleveland, ohio, u.s.a. seventh printing, december 2001 document number: 2000-900-01 rev. g manual print history the print history shown below lists the printing dates of all revisions and addenda created for this manual. the revision level letter increases alphabetically as the manual undergoes subsequent updates. addenda, which are released between revisions, contain important change information that the user should incorporate immediately into the manual. addenda are numbered sequentially. when a new revision is created, all addenda associated with the previous revision of the manual are incorporated into the new revision of the manual. each new revision includes a revised copy of this print history page. revision a (document number 2000-900-01).............................................................. november 1994 revision b (document number 2000-900-01)................................................................ february 1995 revision c (document number 2000-900-01).................................................................... march 1995 addendum c (document number 2000-900-02) .................................................................. april 1995 revision d (document number 2000-900-01)................................................................... august 1995 addendum d (document number 2000-900-02) .............................................................. october 1995 addendum d (document number 2000-900-03) ..........................................................september 1996 revision e (document number 2000-900-01) .................................................................... march 1997 revision f (document number 2000-900-01) ...................................................................... april 1999 revision g (document number 2000-900-01).............................................................. december 2001 all keithley product names are trademarks or registered trademarks of keithley instruments, inc. other brand names are trademarks or registered trademarks of their respective holders. the following safety precautions should be observed before using this product and any associated instrumentation. although some instruments and accessories would normally be used with non-hazardous voltages, there are situations where hazardous conditions may be present. this product is intended for use by qualited personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury. read and follow all installation, operation, and maintenance information carefully before us - ing the product. refer to the manual for complete product specitcations. if the product is used in a manner not specited, the protection provided by the product may be impaired. the types of product users are: responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that the equip- ment is operated within its specitcations and operating limits, and for ensuring that operators are adequately trained. operators use the product for its intended function. they must be trained in electrical safety procedures and proper use of the instrument. they must be protected from electric shock and contact with hazardous live circuits. maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting the line voltage or replacing consumable materials. maintenance procedures are described in the manual. the procedures explicitly state if the operator may perform them. otherwise, they should be performed only by service personnel. service personnel are trained to work on live circuits, and perform safe installations and repairs of products. only properly trained service personnel may perform installation and service procedures. keithley products are designed for use with electrical signals that are rated installation category i and installation category ii, as described in the international electrotechnical commission (iec) standard iec 60664. most measurement, control, and data i/o signals are installation category i and must not be directly connected to mains voltage or to voltage sources with high tra n- sient over-voltages. installation category ii connections require protection for high transient over-voltages often associated with local ac mains connections. assume all measurement, control, and data i/o connections are for connection to category i sourc- es unless otherwise marked or described in the manual. exercise extreme caution when a shock hazard is present. lethal voltage may be present on cable connector jacks or test txtures . the american national standards institute (ansi) states that a shock hazard exists when voltage levels greater than 30v rms, 42.4v peak, or 60vdc are present. a good safety practice is to expect that hazardous voltage is present in any unknown circuit before measuring. operators of this product must be protected from electric shock at all times. the responsible body must ensure that operators are prevented access and/or insulated from every connection point. in some cases, connections must be exposed to potential human contact. product operators in these circumstances must be trained to protect themselves from the risk of electric shock. if the circuit is capable of operating at or above 1000 volts, no conductive part of the circuit may be exposed. do not connect switching cards directly to unlimited power circuits. they are intended to be used with impedance limited sourc- es. never connect switching cards directly to ac mains. when connecting sources to switching cards, install protective de- vices to limit fault current and voltage to the card. before operating an instrument, make sure the line cord is connected to a properly grounded power receptacle. inspect the con- necting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use. when installing equipment where access to the main power cord is restricted, such as rack mounting, a separate main input pow- er disconnect device must be provided, in close proximity to the equipment and within easy reach of the operator. for maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under test. always remove power from the entire test system and discharge any capacitors before: connecting or disconnecting ca- bles or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers. s afety precautions do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) gr ound. al- ways make measurements with dry hands while standing on a dry, insulated surface capable of withstanding the voltage being meas ured. the instrument and accessories must be used in accordance with its specitcations and operating instructions or the safety of th e equipment may be impaired. do not exceed the maximum signal levels of the instruments and accessories, as detned in the specitcations and operating in- formation, and as shown on the instrument or test txture panels, or switching card. when fuses are used in a product, replace with same type and rating for continued protection against tre hazard. chassis connections must only be used as shield connections for measuring circuits, not as safety earth ground connections. if you are using a test txture, keep the lid closed while power is applied to the device under test. safe operation requires th e use of a lid interlock. if a screw is present, connect it to safety earth ground using the wire recommended in the user documentation. the symbol on an instrument indicates that the user should refer to the operating instructions located in the manual. the symbol on an instrument shows that it can source or measure 1000 volts or more, including the combined effect of normal and common mode voltages. use standard safety precautions to avoid personal contact with these voltages. the warning heading in a manual explains dangers that might result in personal injury or death. always read the associated information very carefully before performing the indicated procedure. the caution heading in a manual explains hazards that could damage the instrument. such damage may invalidate the war- ranty. instrumentation and accessories shall not be connected to humans. before performing any maintenance, disconnect the line cord and all test cables. to maintain protection from electric shock and tre, replacement components in mains circuits, including the power transformer, test leads, and input jacks, must be purchased from keithley instruments. standard fuses, with applicable national safety ap- provals, may be used if the rating and type are the same. other components that are not safety related may be purchased from other suppliers as long as they are equivalent to the original component. (note that selected parts should be purchased only through keithley instruments to maintain accuracy and functionality of the product.) if you are unsure about the applicability of a replacement component, call a keithley instruments oftce for information. to clean an instrument, use a damp cloth or mild, water based cleaner. clean the exterior of the instrument only. do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. products that consist of a circuit boa rd with no case or chassis (e.g., data acquisition board for installation into a computer) should never require cleaning if handled acc ord- ing to instructions. if the board becomes contaminated and operation is affected, the board should be returned to the factory f or proper cleaning/servicing. ! 11/01 table of contents 1 general information introduction..........................................................................................1-2 feature overview..................................................................................1-2 warranty information...........................................................................1-3 manual addenda...................................................................................1-3 safety symbols and terms ....................................................................1-3 speci?ations.......................................................................................1-3 inspections ...........................................................................................1-4 options and accessories.......................................................................1-5 2 basic measurements introduction..........................................................................................2-2 front panel summary ...........................................................................2-3 rear panel summary ............................................................................2-6 power-up ..............................................................................................2-8 display...............................................................................................2-17 measuring voltage..............................................................................2-18 measuring current..............................................................................2-22 measuring resistance .........................................................................2-24 measuring frequency and period .......................................................2-26 measuring temperature ......................................................................2-28 math...................................................................................................2-30 measuring continuity .........................................................................2-34 testing diodes ....................................................................................2-35 3 measurement options introduction..........................................................................................3-2 measurement con?uration .................................................................3-3 trigger operations................................................................................3-8 buffer operations ...............................................................................3-17 limit operations.................................................................................3-20 scan operations..................................................................................3-22 system operations..............................................................................3-32 4 remote operation introduction..........................................................................................4-2 selecting a language ............................................................................4-4 rs-232 operation .................................................................................4-6 gpib bus operation and reference .......................................................4-9 status structure...................................................................................4-19 trigger model (gpib operation) ....................................................... 4-29 programming syntax ......................................................................... 4-32 common commands.......................................................................... 4-39 5 scpi command reference scpi signal oriented measurement commands .................................. 5-3 scpi command subsystems reference tables ...................................... 5-7 calculate subsystem .......................................................................... 5-20 display subsystem............................................................................ 5-26 :format subsystem .......................................................................... 5-28 route subsystem ............................................................................. 5-32 [sense[1]] subsystem ...................................................................... 5-37 status subsystem............................................................................. 5-52 :system subsystem.......................................................................... 5-61 :trace subsystem............................................................................ 5-68 trigger subsystem ............................................................................. 5-70 :unit subsystem............................................................................... 5-74 a speci?ations accuracy calculations......................................................................... a-7 optimizing measurement accuracy .................................................. a-10 optimizing measurement speed ....................................................... a-11 b status and error messages c example programs program examples .............................................................................. c-2 d models 196/199 and 8840a/8842a commands e ieee-488 bus overview introduction .........................................................................................e-2 bus description ....................................................................................e-4 bus lines ..............................................................................................e-6 bus commands ....................................................................................e-8 interface function codes ....................................................................e-15 f ieee-488 and scpi conformance information introduction .........................................................................................f-2 list of illustrations 2 basic measurements model 2000 front panel .......................................................................2-3 model 2000 rear panel .........................................................................2-6 power module ......................................................................................2-8 dc and ac voltage measurements ....................................................2-19 dc and ac current measurements.....................................................2-22 two- and four-wire resistance measurements....................................2-25 frequency and period measurements.................................................2-27 thermocouple temperature measurements ........................................2-28 continuity measurements ..................................................................2-34 diode testing......................................................................................2-35 3 measurement options moving average and repeating ?ters...................................................3-4 front panel triggering without stepping/scanning ...............................3-8 rear panel pinout...............................................................................3-11 trigger link input pulse speci?ations (ext trig) .........................3-12 trigger link output pulse speci?ations (vmc) ................................3-12 dut test system ................................................................................3-13 trigger link connections ....................................................................3-13 operation model for triggering example ...........................................3-14 din to bnc trigger cable..................................................................3-16 buffer locations..................................................................................3-18 using limit test to sort 100 ? , 10% resistors......................................3-21 front panel triggering with stepping..................................................3-24 front panel triggering with scanning.................................................3-25 internal scanning example with reading count option .......................3-27 internal scanning example with timer and delay options ..................3-29 external scanning example with model 7001 ...................................3-31 4 remote operation rs-232 interface connector .................................................................4-8 ieee-488 connector...........................................................................4-10 ieee-488 connections .......................................................................4-10 ieee-488 connector location.............................................................4-11 model 2000 status register structure..................................................4-19 standard event status .........................................................................4-22 operation event status........................................................................4-22 measurement event status ..................................................................4-23 questionable event status...................................................................4-23 status byte and service request (srq).............................................4-25 trigger model (gpib operation)........................................................4-29 device action (trigger model)............................................................ 4-31 standard event enable register........................................................... 4-41 standard event status register ............................................................ 4-43 service request enable register .......................................................... 4-49 status byte register ............................................................................ 4-51 5 scpi command reference ascii data format ............................................................................. 5-28 ieee754 single precision data format (32 data bits)......................... 5-29 ieee754 double precision data format (64 data bits) ....................... 5-29 measurement event register............................................................... 5-53 questionable event register ............................................................... 5-54 operation event register .................................................................... 5-55 measurement event enable register ................................................... 5-57 questionable event enable register .................................................... 5-57 operation event enable register ......................................................... 5-57 key-press codes................................................................................. 5-66 e ieee-488 bus overview ieee-488 bus con?uration ................................................................e-5 ieee-488 handshake sequence ...........................................................e-7 command codes ................................................................................e-12 list of tables 2 basic measurements fuse ratings..........................................................................................2-9 factory defaults..................................................................................2-13 crest factor limitations ......................................................................2-18 3 measurement options rate settings for the measurement functions .......................................3-7 auto delay settings ..............................................................................3-9 bus commands parameters for stepping and scanning counters .......3-28 4 remote operation language supported.............................................................................4-4 rs-232 connector pinout .....................................................................4-8 general bus commands and associated statements............................4-14 ieee-488.2 common commands and queries....................................4-39 5 scpi command reference signal oriented measurement command summary ..............................5-3 calculate command summary ..........................................................5-8 display command summary ...............................................................5-9 format command summary ..............................................................5-9 route command summary ..............................................................5-10 sense command summary ...............................................................5-10 status command summary ..............................................................5-16 system command summary ............................................................5-17 trace command summary ..............................................................5-17 trigger command summary...............................................................5-18 unit command summary .................................................................5-19 b status and error messages status and error messages................................................................... b-2 d models 196/199 and 8840a/8842a commands models 196/199 device-dependent command summary ....................d-2 models 8840a/8842a device-dependent command summary..........................................................................................d-6 e ieee-488 bus overview ieee-488 bus command summary ..................................................... e-8 hexadecimal and decimal command codes ...................................... e-11 typical addressed command sequence ............................................. e-13 typical addressed command sequence ............................................. e-13 ieee command groups ..................................................................... e-14 model 2000 interface function codes ............................................... e-15 f ieee-488 and scpi conformance information ieee-488 documentation requirements.............................................. f-2 coupled commands ............................................................................ f-4 1 general information introduction this section contains general information about the model 2000 multimeter. the information is organized as follows: feature overview warranty information manual addenda safety symbols and terms speci?ations inspection options and accessories if you have any questions after reviewing this information, please contact your local keithley representative or call one of our applications engineers at 1-800-348-3735 (u.s. and canada only). worldwide phone numbers are listed at the front of this manual. feature overview the model 2000 is a 6 ? -digit high-performance digital multimeter. it has 0.002% 90-day basic dc voltage accuracy and 0.008% 90-day basic resistance accuracy. at 6 ? digits, the mul- timeter delivers 50 triggered readings/sec over the ieee-488 bus. at 4 ? digits, it can read up to 2000 readings/sec into its internal buffer. the model 2000 has broad measurement ranges: dc voltage from 0.1 v to 1000v. ac (rms) voltage from 0.1 v to 750v, 1000v peak. dc current from 10na to 3a. ac (rms) current from 1 a to 3a. two and four-wire resistance from 100 ? to 120m ? . frequency from 3hz to 500khz. thermocouple temperature from -200? to +1372?. some additional capabilities of the model 2000 include: full range of functions ?in addition to those listed above, the model 2000 functions include period, db, dbm, continuity, diode testing, mx+b, and percent. optional scanning ?for internal scanning, options include the model 2000-scan, a 10-channel, general-purpose card, and the model 2001-tcscan, a 9-channel, thermo- couple card with a built-in cold junction. for external scanning, the model 2000 is com- patible with keithley's model 7001 and 7002 switch matrices and cards. programming languages and remote interfaces ?the model 2000 offers three program- ming language choices (scpi, keithley models 196/199, and fluke 8840a/8842a) and two remote interface ports (ieee-488/gpib and rs-232c). reading and setup storage ?up to 1024 readings and two setups (user and factory de- faults) can be stored and recalled. closed-cover calibration ?the instrument can be calibrated either from the front panel or remote interface. 1-2 general information warranty information warranty information is located at the front of this instruction manual. should your model 2000 require warranty service, contact the keithley representative or authorized re- pair facility in your area for further information. when returning the instrument for repair, be sure to ?l out and include the service form at the back of this manual to provide the re- pair facility with the necessary information. manual addenda any improvements or changes concerning the instrument or manual will be explained in an addendum included with the manual. be sure to note these changes and incorporate them into the manual. safety symbols and terms the following symbols and terms may be found on the instrument or used in this manual. the symbol on the instrument indicates that the user should refer to the operating in- structions located in the manual. the symbol on the instrument shows that high voltage may be present on the terminal(s). use standard safety precautions to avoid personal contact with these voltages. the warning heading used in this manual explains dangers that might result in personal injury or death. always read the associated information very carefully before performing the indicated procedure. the caution heading used in this manual explains hazards that could damage the in- strument. such damage may invalidate the warranty. speci?ations full model 2000 speci cations are included in appendix a. ! general information 1-3 inspection the model 2000 was carefully inspected electrically and mechanically before shipment. after unpacking all items from the shipping carton, check for any obvious signs of physical damage that may have occurred during transit. (note: there may be a protective ?m over the display lens, which can be removed.) report any damage to the shipping agent immediately. save the original packing carton for possible future reshipment. the following items are included with every model 2000 order: model 2000 multimeter with line cord. safety test leads (model 1751). accessories as ordered. certi?ate of calibration. model 2000 user's manual (p/n 2000-900-00). model 2000 calibration manual (p/n 2000-905-00). model 2000 support software disk including testpoint run-time applications, testpoint instrument libraries for gpib and rs-232, and quickbasic examples. if an additional manual is required, order the appropriate manual package. the manual pack- ages include a manual and any pertinent addenda. 1-4 general information options and accessories the following options and accessories are available from keithley for use with the model 2000. scanner cards model 2000-scan: this is a 10-channel scanner card that installs in the option slot of the model 2000. channels can be con gured for 2-pole or 4-pole operation. included are two pairs of leads for connection to model 2000 rear panel inputs (keithley p/n ca-109). model 2001-tcscan: this is a thermocouple scanner card that installs in the option slot of the model 2000. the card has nine analog input channels that can be used for high-accuracy, high-speed scanning. a built-in temperature reference allows multi-channel, cold-junction com- pensated temperature measurements using thermocouples. general purpose probes model 1754 universal test lead kit: consists of one set of test leads (0.9m), two spade lugs, two banana plugs, two hooks, and two alligator clips. model 8605 high performance modular test leads: consists of two high voltage (1000v) test probes and leads. the test leads are terminated with a banana plug with retractable sheath on each end. model 8606 high performance probe tip kit: consists of two spade lugs, two alligator clips, and two spring hook test probes. (the spade lugs and alligator clips are rated at 30v rms, 42.4v peak; the test probes are rated at 1000v.) these components are for use with high perfor- mance test leads terminated with banana plugs, such as the model 8605. the following test leads and probes are rated at 30v rms, 42.4v peak: models 5805 and 5805-12 kelvin probes: consists of two spring-loaded kelvin test probes with banana plug termination. designed for instruments that measure 4-terminal resistance. the model 5805 is 0.9m long; the model 5805-12 is 3.6m long. model 5806 kelvin clip lead set: includes two kelvin clip test leads (0.9m) with banana plug termination. designed for instruments that measure 4-terminal resistance. a set of eight replacement rubber bands is available as keithley p/n ga-22. model 8604 smd probe set: consists of two test leads (0.9m), each terminated with a sur- face mount device ?rabber?clip on one end and a banana plug with a retractable sheath on the other end. general information 1-5 low thermal probes model 8610 low thermal shorting plug: consists of four banana plugs mounted to a 1- inch square circuit board, interconnected to provide a short circuit among all plugs. model 8611 low thermal patch leads: consists of two test leads (0.9m), each with a banana plug with a retractable sheath at each end. these leads minimize the thermally-induced offsets that can be created by test leads. model 8612 low thermal spade leads: consists of two test leads (0.9m), each terminated with a spade lug on one end and a banana plug with a retractable sheath on the other end. these leads minimize the thermally-induced offsets that can be created by test leads. cables and adapters models 7007-1 and 7007-2 shielded gpib cables: connect the model 2000 to the gpib bus using shielded cables and connectors to reduce electromagnetic interference (emi). the model 7007-1 is 1m long; the model 7007-2 is 2m long. models 8501-1 and 8501-2 trigger link cables: connect the model 2000 to other instru- ments with trigger link connectors (e.g., model 7001 switch system). the model 8501-1 is 1m long; the model 8501-2 is 2m long. model 8502 trigger link adapter: allows you to connect any of the six trigger link lines of the model 2000 to instruments that use the standard bnc trigger connectors. model 8504 din to bnc trigger cable: allows you to connect trigger link lines one (voltmeter complete) and two (external trigger) of the model 2000 to instruments that use bnc trigger connectors. the model 8504 is 1m long. rack mount kits model 4288-1 single fixed rack mount kit: mounts a single model 2000 in a standard 19- inch rack. model 4288-2 side-by-side rack mount kit: mounts two instruments (models 182, 428, 486, 487, 2000, 2001, 2002, 6517, 7001) side-by-side in a standard 19-inch rack. model 4288-3 side-by-side rack mount kit: mounts a model 2000 and a model 199 side- by-side in a standard 19-inch rack. model 4288-4 side-by-side rack mount kit: mounts a model 2000 and a 5.25-inch instru- ment (models 195a, 196, 220, 224, 230, 263, 595, 614, 617, 705, 740, 775, etc.) side-by-side in a standard 19-inch rack. carrying case model 1050 padded carrying case: a carrying case for a model 2000. includes handles and shoulder strap. 1-6 general information 2 basic measurements introduction this section summarizes front panel operation of the model 2000. it is organized as follows: front panel summary includes an illustration and summarizes keys, display, and connections. rear panel summary includes an illustration and summarizes connections. power-up describes connecting the instrument to line power, the power-up sequence, the warm-up time, and default conditions. display discusses the display format and messages that may appear while using the instrument. measuring voltage covers dc and ac voltage measurement connections and low level voltage considerations. measuring current covers dc and ac current measurement connections and current fuse replacement. measuring resistance details two and four-wire measurement connections and shielding considerations. measuring frequency and period covers frequency and period measurement con- nections. measuring temperature describes the use of thermocouples for temperature mea- surements. math covers the mx+b, percent, dbm, and db math functions performed on single readings. measuring continuity explains setting up and measuring continuity of a circuit. testing diodes describes testing general-purpose and zener diodes. 2-2 basic measurements front panel summary the front panel of the model 2000 is shown in figure 2-1. this ?ure includes important ab- breviated information that should be reviewed before operating the instrument. 1 function keys (shifted and unshifted) select measurement function (dc and ac voltage, dc and ac current, 2-wire and 4-wire re- sistance, frequency, period, temperature with thermocouples), math function (mx+b, %, dbm, db), or special function (continuity, diode test). 2 operation keys extrig selects external triggers (front panel, bus, trigger link) as the trigger source. trig triggers a measurement from the front panel. store enables reading storage. recall displays stored readings and buffer statistics (maximum, minimum, average, standard deviation). use and to scroll through buffer; use and to toggle between reading number and reading. filter displays digital ?ter status for present function and toggles ?ter on/off. rel enables/disables relative reading on present function. and moves through selections within functions and operations. if scanner card in- stalled, manually scans channels. open opens all channels on internal scanner card; stops scanning. close closes selected internal channel. step steps through channels; sends a trigger after each channel. scan scans through channels; sends a trigger after last channel. digits changes number of digits of resolution. rate changes reading rate: fast, medium, slow. exit cancels selection, moves back to measurement display. enter accepts selection, moves to next choice or back to measurement display. shift used to access shifted keys. local cancels gpib remote mode. 8 5 4 6 7 1 3 2 2000 multimeter range ! f 500v peak front/rear 3a 250v amps hi lo inputs 350v peak 1000v peak auto shift local power range r shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch8 ch9 ch10 hold trig fast med slow auto err input sense ? 4 wire exit enter digits rate rel filter trig ex trig store recall open close dcv dci mx+b % dbm acv aci ? 2 ? 4 freq temp db cont period tcoupl limits on/off delay hold save setup config halt test rs232 gpib cal step scan basic measurements 2-3 figure 2-1 model 2000 front panel ) ) ) 3 shifted operation keys delay sets user delay between trigger and measurement. hold holds reading when the selected number of samples is within the selected tol- erance. limits sets upper and lower limit values for readings. on/off enables/disables limits; selects beeper operation for limit testing. test selects built-in tests, diagnostics, display test. cal accesses calibration. save saves present con?uration for power-on user default. setup restores factory or user default con?uration. config selects minimum/maximum channels, timer, and reading count for step/scan. halt turns off step/scan. gpib enables/disables gpib interface; selects address and language. rs232 enables/disables rs-232 interface; selects baud rate, ?w control, terminator. 4 range keys moves to higher range; increments digit; moves to next selection. moves to lower range; decrements digit; moves to previous selection. auto enables/disables autorange. 5 annunciators *(asterisk) reading being stored. (diode) instrument is in diode testing function. (speaker) beeper on for continuity or limits testing. (more) indicates additional selections are available. 4w 4-wire resistance reading displayed. auto autoranging enabled. buffer recalling stored readings. ch 1-10 displayed internal channel is closed. err questionable reading; invalid cal step. fast fast reading rate. filt digital ?ter enabled. hold instrument is in hold mode. lstn instrument addressed to listen over gpib. math math function (mx+b, %, db, dbm) enabled. med medium reading rate. rear reading acquired from rear inputs. rel relative reading displayed. rem instrument is in gpib remote mode. scan instrument is in scan mode. shift accessing shifted keys. slow slow reading rate. srq service request over gpib. stat displaying buffer statistics. step instrument is in step mode. talk instrument addressed to talk over gpib. timer timed scans in use. trig indicates external trigger (front panel, bus, trigger link) selected. 2-4 basic measurements 6 input connections input hi and lo used for making dc volts, ac volts, 2-wire resistance measurements. amps used in conjunction with input lo to make dc current and ac cur- rent measurements. also holds current input fuse (3a, 250v, fast blow, 5 20mm). sense ? 4 wire used with input hi and lo to make 4-wire resistance measure- hi and lo ments. 7 inputs selects input connections on front or rear panel. 8 handle pull out and rotate to desired position. basic measurements 2-5 rear panel summary the rear panel of the model 2000 is shown in figure 2-2. this ?ure includes important ab- breviated information that should be reviewed before operating the instrument. warning: no internal operator servicable parts,service by qualified personnel only. warning: no internal operator servicable parts,service by qualified personnel only. caution: for continued protection against fire hazard,replace fuse with same type and rating. caution: for continued protection against fire hazard,replace fuse with same type and rating. rs232 1 3 5 2 4 6 vmc ext trig fuse line 250mat (sb) 100 vac 120 vac 125mat (sb) 220 vac 240 vac 120 2 1 34 5 6 #1 1 2 3 4 5 6 7 8 made in u.s.a. input 500v peak 350v peak 1000v peak trigger link sense ? 4w hi lo ! line rating 50, 60 400hz 17 va max ieee-488 (change ieee address from front panel) ! ! ! #2 external trigger input trigger reading >72 sec ttl hi ttl lo reading complete volt meter complete output >10 sec ttl hi ttl lo 2-6 basic measurements figure 2-2 model 2000 rear panel 1 option slot an optional scanner card (model 2000-scan, 2001-scan, or 2001-tcscan) installs in this slot. 2 input connections input hi and lo used for making dc volts, ac volts, 2-wire resistance measurements and for connecting scanner card. sense ? 4 wire used with input hi and lo to make 4-wire resistance measurements hi and lo and also for connecting scanner card. 3 trigger link one 8-pin micro-din connector for sending and receiving trigger pulses among other instru- ments. use a trigger link cable or adapter, such as models 8501-1, 8501-2, 8502, 8504. 4 rs-232 connector for rs-232 operation. use a straight-through (not null modem) db-9 cable. 5 ieee-488 connector for ieee-488 (gpib) operation. use a shielded cable, such as models 7007-1 and 7007-2. 6 power module contains the ac line receptacle, power line fuse, and line voltage setting. the model 2000 can be con?ured for line voltages of 100v/120v/220v/240vac at line frequencies of 45hz to 66hz or 360hz to 440hz. basic measurements 2-7 power-up line power connection follow the procedure below to connect the model 2000 to line power and turn on the instrument. 1. check to see that the line voltage selected on the rear panel (see figure 2-3) is correct for the operating voltage in your area. if not, refer to the next procedure, ?etting line voltage and replacing fuse. caution operating the instrument on an incorrect line voltage may cause damage to the instrument, possibly voiding the warranty. 2. before plugging in the power cord, make sure that the front panel power switch is in the off (0) position. 3. connect the female end of the supplied power cord to the ac receptacle on the rear panel. connect the other end of the power cord to a grounded ac outlet. warning the power cord supplied with the model 2000 contains a separate ground wire for use with grounded outlets. when proper connections are made, instrument chassis is connected to power line ground through the ground wire in the power cord. failure to use a grounded outlet may result in per- sonal injury or death due to electric shock. 4. turn on the instrument by pressing the front panel power switch to the on (1) position. model 2000 warning: no internal operator servicable parts,service by qualified personnel only. warning: no internal operator servicable parts,service by qualified personnel only. caution: for continued protection against fire hazard,replace fuse with same type and rating. caution: for continued protection against fire hazard,replace fuse with same type and rating. rs232 1 3 5 2 4 6 vmc ext trig fuse line 250mat (sb) 100 vac 120 vac 125mat (sb) 220 vac 240 vac 120 made in u.s.a. input 500v peak 350v peak 1000v peak trigger link sense ? 4w hi lo ! line rating 50, 60 400hz 17 va max ieee-488 (change ieee address from front panel) ! ! ! 120 240 220 100 fuse spring window line voltage selector fuse holder assembly 2-8 basic measurements figure 2-3 power module setting line voltage and replacing fuse a rear panel fuse located next to the ac receptacle protects the power line input of the instru- ment. if the line voltage setting needs to be changed or the line fuse needs to be replaced, per- form the following steps. warning make sure the instrument is disconnected from the ac line and other equip- ment before changing the line voltage setting or replacing the line fuse. 1. place the tip of a at-blade screwdriver into the power module by the fuse holder assem- bly (see figure 2-3). gently push in and to the left. release pressure on the assembly and its internal spring will push it out of the power module. 2. remove the fuse and replace it with the type listed in table 2-1. caution for continued protection against ?e or instrument damage, only replace fuse with the type and rating listed. if the instrument repeatedly blows fuses, locate and correct the cause of the trouble before replacing the fuse. see the optional model 2000 repair manual for troubleshooting information. 3. if con?uring the instrument for a different line voltage, remove the line voltage selector from the assembly and rotate it to the proper position. when the selector is installed into the fuse holder assembly, the correct line voltage appears inverted in the window. 4. install the fuse holder assembly into the power module by pushing it in until it locks in place. table 2-1 fuse ratings line voltage fuse rating keithley p/n 100/120v 220/240v 0.25a slow-blow 5 20mm 0.125a slow-blow 5 20mm fu-96-4 fu-91 basic measurements 2-9 power-up sequence on power-up, the model 2000 performs self-tests on its eprom and ram and momentarily lights all segments and annunciators. if a failure is detected, the instrument momentarily dis- plays an error message and the err annunciator turns on. (error messages are listed in appen- dix b.) note if a problem develops while the instrument is under warranty, return it to keithley instruments, inc., for repair. if the instrument passes the self-tests, the rmware revision levels are displayed. an example of this display is: rev: a01 a02 where: a01 is the main board rom revision. a02 is the display board rom revision. after the power-up sequence, the instrument begins its normal display of readings. 2-10 basic measurements high energy circuit safety precautions to optimize safety when measuring voltage in high energy distribution circuits, read and use the directions in the following warning. warning dangerous arcs of an explosive nature in a high energy circuit can cause severe personal injury or death. if the multimeter is connected to a high energy circuit when set to a current range, low resistance range, or any other low impedance range, the circuit is virtually shorted. dangerous arcing can result even when the multimeter is set to a voltage range if the minimum volt- age spacing is reduced in the external connections. when making measurements in high energy circuits, use test leads that meet the following requirements: test leads should be fully insulated. only use test leads that can be connected to the circuit (e.g., alligator clips, spade lugs, etc.) for hands-off measurements. do not use test leads that decrease voltage spacing. these diminishes arc protection and create a hazardous condition. use the following sequence when testing power circuits: 1. de-energize the circuit using the regular installed connect-disconnect device, such as a circuit breaker, main switch, etc. 2. attach the test leads to the circuit under test. use appropriate safety rated test leads for this application. 3. set the multimeter to the proper function and range. 4. energize the circuit using the installed connect-disconnect device and make measure- ments without disconnecting the multimeter. 5. de-energize the circuit using the installed connect-disconnect device. 6. disconnect the test leads from the circuit under test. warning the maximum common-mode voltage (voltage between input lo and the chassis ground) is 500v peak. exceeding this value may cause a breakdown in insulation, creating a shock hazard. basic measurements 2-11 power-on defaults power-on defaults are the settings the instrument assumes when it is turned on. the model 2000 offers two choices for the settings: factory and user. the power-on default will be the last con?uration you saved. the save and setup keys select the two choices of power-on defaults. to save present con guration as user settings: 1. con?ure the instrument as desired for user default. 2. press shift then save. 3. use the and keys to select yes or no. 4. press enter. to restore factory or user settings: 1. press shift then setup. 2. use the and keys to select factory or user. 3. press enter. since the basic measurement procedures in this manual assume the factory defaults, reset the instrument to the factory settings when following step-by-step procedures. table 2-2 lists the factory default settings. 2-12 basic measurements table 2-2 factory defaults setting factory default autozero buffer continuity beeper digits rate threshold current (ac and dc) digits (ac) digits (dc) filter count mode range relative value rate (ac) rate (dc) diode test digits range rate frequency and period digits range relative value rate function gpib address language limits beeper high limit low limit mx+b scale factor offset percent references on no effect on 4 ? fast (0.1 plc) 10 ? 5 ? 6 ? on 10 moving average auto off 0.0 medium* medium (1 plc) 6 ? 1ma medium (1 plc) 6 ? 10v off 0.0 slow (1 sec) dcv no effect (16 at factory) (scpi at factory) off never +1 -1 off 1.0 0.0 off 1.0 basic measurements 2-13 resistance (2-wire and 4-wire) digits filter count mode range relative value rate rs-232 baud flow tx term scanning channels mode temperature digits filter count mode junction temperature relative value rate thermocouple units triggers continuous delay source ?? on 10 moving average auto off 0.0 medium (1 plc) off no effect no effect no effect off 1-10 internal 5 ? on 10 moving average simulated 23? off 0.0 medium (1 plc) j ? on auto immediate table 2-2 (cont.) factory defaults setting factory default 2-14 basic measurements voltage (ac and dc) db reference dbm reference digits (ac) digits (dc) filter count mode range relative value rate (ac) rate (dc) no effect 75 ? 5 ? ?? on 10 moving average auto off 0.0 medium* medium (1 plc) *detector:bandwidth 30 table 2-2 (cont.) factory defaults setting factory default basic measurements 2-15 gpib primary address the gpib primary address of the instrument must be the same as the primary address you specify in the controller s programming language. the default primary address of the instru- ment is 16, but you can set the address to any value from 0 to 30 by using the following step by step instructions. 1. press shift then gpib. 2. use the and keys to select address. or, press enter. once you have pressed enter, the unit automatically displays the address selection. 3. use the and keys to toggle from address to the numeric entry. notice the val- ues are blinking. 4. use the and keys to change the numeric entries to the desired address. 5. press enter. see section four ?remote operation for more gpib information. warm-up time the model 2000 is ready for use as soon as the power-up sequence has completed. however, to achieve rated accuracy, allow the instrument to warm up for one hour. if the instrument has been subjected to extreme temperatures, allow additional time for internal temperatures to stabilize. 2-16 basic measurements display the display of the model 2000 is primarily used to display readings, along with the units and type of measurement. annunciators are located on the top, bottom, right, and left of the reading or message display. the annunciators indicate various states of operation. see figure 2-1 for a complete listing of annunciators. status and error messages status and error messages are displayed momentarily. during model 2000 operation and pro- gramming, you will encounter a number of front panel messages. typical messages are either of status or error variety, as listed in appendix b. basic measurements 2-17 measuring voltage the model 2000 can make dcv measurements from 0.1? to 1000v and acv measure- ments from 0.1? to 750v rms, 1000v peak. connections assuming factory default conditions, the basic procedure is as follows: 1. connect test leads to the input hi and lo terminals. either the front or rear inputs can be used; place the inputs button in the appropriate position. 2. select the measurement function by pressing dcv or acv. 3. pressing auto toggles autoranging. notice the auto annunciator is displayed with autoranging. if you want manual ranging, use the range and keys to select a measurement range consistent with the expected voltage. 4. connect test leads to the source as shown in figure 2-4. caution do not apply more than 1000v peak to the input or instrument damage may occur. the voltage limit is subject to the 8 10 7 v?z product. 5. observe the display. if the ?verflow?message is displayed, select a higher range until an o normal reading is displayed (or press auto for autoranging). use the lowest possible range for the best resolution. 6. take readings from the display. crest factor ac voltage and current accuracies are affected by the crest factor of the waveform, the ratio of the peak value to the rms value. table 2-3 lists the fundamental frequencies at which the cor- responding crest factor must be taken into account for accuracy calculations. table 2-3 crest factor limitations crest factor fundamental frequency 2 3 4-5 50khz 3khz 1khz 2-18 basic measurements low level considerations for sensitive measurements, external considerations beyond the model 2000 affect the accu- racy. effects not noticeable when working with higher voltages are signi cant in microvolt sig- nals. the model 2000 reads only the signal received at its input; therefore, it is important that this signal be properly transmitted from the source. the following paragraphs indicate factors that affect accuracy, including stray signal pick-up and thermal offsets. shielding ac voltages that are extremely large compared with the dc signal to be measured may pro- duce an erroneous output. therefore, to minimize ac interference, the circuit should be shield- ed with the shield connected to the model 2000 input lo (particularly for low level sources). improper shielding can cause the model 2000 to behave in one or more of the following ways: unexpected offset voltages. inconsistent readings between ranges. sudden shifts in reading. to minimize pick-up, keep the voltage source and the model 2000 away from strong ac mag- netic sources. the voltage induced due to magnetic ux is proportional to the area of the loop formed by the input leads. therefore, minimize the loop area of the input leads and connect each signal at only one point. note shielded cables should be used for input circuits to avoid interference caused by conducting rf. 2001 multimeter caution : maximum input = 750v rms, 1000v peak, 8 x 10 7 v?z ac voltage source model 2000 input impedence = 1m ? shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err 2001 multimeter model 2000 caution : maximum input = 1010v peak dc voltage source input resistance = 10m ? ? shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch8 ch9 ch10 hold trig fast med slow auto err basic measurements 2-19 figure 2-4 dc and ac voltage measurements thermal emfs thermal emfs (thermoelectric potentials) are generated by thermal differences between the junctions of dissimilar metals. these can be large compared to the signal that the model 2000 can measure. thermal emfs can cause the following conditions: instability or zero offset is much higher than expected. the reading is sensitive to (and responds to) temperature changes. this effect can be demonstrated by touching the circuit, by placing a heat source near the circuit, or by a regular pattern of instability (corresponding to changes in sunlight or the activation of heating and air conditioning systems). to minimize the drift caused by thermal emfs, use copper leads to connect the circuit to the model 2000. a banana plug generates a few microvolts. a clean copper conductor such as #10 bus wire is ideal for this application. the leads to the input may be shielded or unshielded, as necessary. refer to ?hielding? widely varying temperatures within the circuit can also create thermal emfs. therefore, maintain constant temperatures to minimize these thermal emfs. a shielded enclosure around the circuit under test also helps by minimizing air currents. the rel control can be used to null out constant offset voltages. note additional thermals may be generated by the optional scanner cards. 2-20 basic measurements ac voltage offset the model 2000, at 5 ? digits resolution, will typically display 100 counts of offset on ac volts with the input shorted. this offset is caused by the offset of the trms converter. this offset will not affect reading accuracy and should not be zeroed out using the rel feature. the following equation expresses how this offset (v offset ) is added to the signal input (v in ): example: range = 1vac offset = 100 counts (1.0mv) input = 100mv rms the offset is seen as the last digit, which is not displayed. therefore, the offset is negligible. if the rel feature were used to zero the display, the 100 counts of offset would be subtracted from v in , resulting in an error of 100 counts in the displayed reading. see section 3 ?measurement options for information that explain the con guration options for dc and ac voltage measurements. displayed reading v in () 2 v offset () 2 + = displayed reading 100mv () 2 1.0mv () 2 + = displayed reading 0.01v () 110 6 v () + = displayed reading 0.100005 = basic measurements 2-21 measuring current the model 2000 can make dci measurements from 10na to 3a and aci measurements from 1?m to 3a rms. note see the previous discussion about crest factor in ?easuring voltage?in this section. connections assuming factory default conditions, the basic procedure is as follows: 1. connect test leads to the amps and input lo terminals. the front inputs must be used; place the inputs button in the front position. 2. select the measurement function by pressing dci or aci. 3. pressing auto toggles autoranging. notice the auto annunciator is displayed with autoranging. if you want manual ranging, use the range and keys to select a measurement range consistent with the expected current. 4. connect test leads to the source as shown in figure 2-5. caution do not apply more than 3a, 250v to the input or the amps fuse will open- circuit. 5. observe the display. if the ?verflow?message is displayed, select a higher range until a normal reading is displayed (or press auto for autoranging). use the lowest pos- sible range for the best resolution. 6. take readings from the display. 2001 multimeter model 2000 caution : maximum input = 3a dc or rms current source shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err 2-22 basic measurements figure 2-5 dc and ac cur- rent measure- ments amps fuse replacement warning make sure the instrument is disconnected from the power line and other equipment before replacing the amps fuse. 1. turn off the power and disconnect the power line and test leads. 2. from the front panel, gently push in the amps jack with your thumb and rotate the fuse carrier one-quarter turn counter-clockwise. release pressure on the jack and its internal spring will push the jack out of the socket. 3. remove the fuse and replace it with the same type (3a, 250v, fast blow, 5 20mm). the keithley part number is fu-99-1. caution do not use a fuse with a higher current rating than speci?d or instrument damage may occur. if the instrument repeatedly blows fuses, locate and cor- rect the cause of the trouble before replacing the fuse. see the optional model 2000 repair manual for troubleshooting information. 4. install the new fuse by reversing the procedure above. see section 3 ?measurement options for information that explains the con guration op- tions for dc and ac current measurements. basic measurements 2-23 measuring resistance the model 2000 can make 2-wire and 4-wire resistance measurements from 100 ? to 120m ? . connections assuming factory default conditions, the basic procedure is as follows: 1. connect test leads to the model 2000 as follows: a. for ? 2-wire, connect the test leads to input hi and lo. b. for ? 4-wire, connect the test leads to input hi and lo, and sense ? 4 wire hi and lo. recommended kelvin test probes include the keithley models 5805 and 5806. either the front or rear inputs can be used; place the inputs button in the appropriate position. 2. select the measurement function by pressing ? 2 or ? 4. 3. pressing auto toggles autoranging. notice the auto annunciator is displayed with autoranging. if you want manual ranging, use the range and keys to select a measurement range consistent with the expected resistance. 4. connect test leads to the resistance as shown in figure 2-6. caution do not apply more than 1000v peak between input hi and lo or instru- ment damage may occur. 5. observe the display. if the ?verflow?message is displayed, select a higher range until a normal reading is displayed. use the lowest possible range for the best resolution. 6. take a reading from the display. 2-24 basic measurements shielding to achieve a stable reading, it helps to shield resistances greater than 100k ? . place the resis- tance in a shielded enclosure and connect the shield to the input lo terminal of the instrument electrically. see section 3?easurement options for information that explains the con guration options for 2-wire and 4-wire resistance measurements. 2001 multimeter model 2000 resistance under test shielded cable optional shield note: source current flows from the input hi to input lo terminals. shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err 2001 multimeter resistance under test shielded cable optional shield note: source current flows from the input hi to input lo terminals. model 2000 shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err basic measurements 2-25 figure 2-6 two- and four- wire resistance measurements measuring frequency and period the model 2000 can make frequency measurements from 3hz to 500khz on voltage ranges of 100mv, 1v, 10v, 100v, and 750v. period measurements can be taken from 2? to 333ms on the same voltage ranges as the frequency. the instrument uses the volts input terminals to measure frequency. the ac voltage range can be changed with the range and keys. the signal voltage must be greater than 10% of the full-scale range. caution the voltage limit is subject to the 8 10 7 v?z product. trigger level frequency and period use a zero-crossing trigger, meaning that a count is taken when the fre- quency crosses the zero level. the model 2000 uses a reciprocal counting technique to measure frequency and period. this method generates constant measurement resolution for any input fre- quency. the multimeter s ac voltage measurement section performs input signal conditioning. gate time the gate time is the amount of time the model 2000 uses to sample frequency or period read- ings. all settings of the rate key (fast, medium, slow) yield a gate time of one second. the model 2000 completes a reading when it receives its ?st zero-crossing after the gate time expires. in other words, the reading is completed 1/2 cycle after the gate time has expired. for example, with a 1sec gate time to sample a 3hz frequency, you may wait up to 3 seconds before the model 2000 returns a reading. 2-26 basic measurements connections assuming factory default conditions, the basic procedure is as follows: 1. connect test leads to the input hi and lo terminals of the model 2000. either the front or rear inputs can be used; place the inputs button in the appropriate position. 2. select the freq or period function. 3. connect test leads to the source as shown in figure 2-7. caution do not exceed 1000v peak between input hi and input lo or instru- ment damage may occur. 4. take a reading from the display. see section 3?easurement options for information that explains the con guration options for frequency and period measurements. 2001 multimeter model 2000 caution : maximum input = 1000v peak, 8 x 10 7 v hz ac voltage source input impedance = 1m ? shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err basic measurements 2-27 figure 2-7 frequency and period measure- ments measuring temperature the model 2000 measures temperature with thermocouples. the temperature measurement ranges available depend on the type of thermocouple chosen. thermocouples can be connected to the model 2001-tcscan card, which plugs into the op- tion slot of the model 2000, or to an external thermocouple card, such as a model 7057a, 7402, or 7014 installed in a model 7001 or 7002 switch system. connections 2001 multimeter model 2000 shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err out a hi out a lo input lo input hi note: this thermocouple card must be inserted into a keithley model 2000. note: front or rear inputs can be used. + - ch 2 2001-tcscan 2-28 basic measurements figure 2-8 thermocouple temperature measurements con?uration the following information explains the various con?uration options for temperature mea surements. to select and con gure the thermocouple measurement: press shift then tcoupl. three choices are available using the and keys: units ?c, k, f (centigrade, kelvin, fahrenheit). this parameter selects the displayed units for temperature measurements. type ?j, k, t (thermocouple type). junc ?sim, ch1 (simulated or referenced at channel 1). typically, a thermocouple card uses a single reference junction. the model 2000 can simulate a reference junction temperature or use the reference junction on a switching card. typical reference junction temperatures are 0? and 23?. a simulated reference temperature is the temperature of the junction where the thermocouple voltage is sensed. it is room temperature if the thermocouple wire is terminated to banana jacks and corrected directly to the multimeter. the accuracy of a temperature measurement depends on the accuracy of the reference junction. basic measurements 2-29 math model 2000 math operations are divided into four categories: mx+b and percent dbm and db calculations statistics of buffered readings limit testing the ?st two categories are discussed here; buffered reading statistics and reading limit test- ing are described in section 3 ?measurement options. the procedure to select and con gure a math operation is summarized as follows: 1. press shift then the appropriate math key. 2. con?ure the parameters for the math operation. press enter when done. (press shift then the related math function to end the calculation.) notes once enabled for a function, the mx+b and percentage calculations are in effect across function changes. the model 2000 uses ieee-754 oating point format for math calculations. mx + b this math operation lets you manipulate normal display readings (x) mathematically accord- ing to the following calculation: y= mx + b where: x is the normal display reading m and b are user-entered constants for scale factor and offset y is the displayed result 2-30 basic measurements con?uration to con?ure the mx+b calculation, perform the following steps: 1. press shift then mx+b to display the present scale factor: m: +1.000000 ^ 2. enter a value and units pre x. use the and keys to choose a numerical place and use the and keys to increment or decrement the digits. 3. press enter to con rm the m value and display the b value: b: +00.00000 m 4. enter a value and units pre x. 5. press enter to con rm the b value and display the units designation: mxb 6. scroll through the letters to change and press enter when done. the model 2000 then displays the result of the calculation. percent this item selects the percentage calculation and lets you specify a reference value. the dis- played reading will be expressed as a percent deviation from the reference value. the percentage calculation is performed as follows: where: input is the normal display reading. reference is the user entered constant. percent is the displayed result. con?uration to con?ure the percent calculation, perform the following steps: 1. press shift then % to display the present value: ref:+1.000000^ 2. enter a reference sign, value, and units pre x. use the and keys to choose a nu- merical place and use the and keys to increment or decrement the digits. 3. press enter when done. the model 2000 will display the result of the calculation. the result is positive when the input exceeds the reference and negative when the input is less than the reference. engineering units are used to show values in the range 1 nano to 1000g. exponential notation is used above that range. percent input - reference reference ----------------------------------------- - 100% = basic measurements 2-31 dbm calculation dbm is de?ed as decibels above or below a 1mw reference. with a user-programmable ref- erence impedance, the model 2000 reads 0dbm when the voltage needed to dissipate 1mw through the reference impedance is applied. the relationship between dbm, a reference imped- ance, and the voltage is de ned by the following equation: where: v in is the dc or ac input signal. z ref is the speci ed reference impedance. note do not confuse reference impedance with input impedance. the input impedance of the instrument is not modi ed by the dbm parameter. if a relative value is in effect when dbm is selected, the value is converted to dbm then rel is applied to dbm. if rel is applied after dbm has been selected, dbm math has rel applied to it. con?uration to set the reference impedance, perform the following steps: 1. after selecting dbm, the present reference impedance is displayed (1-9999 ? ): ref: 0000 2. to change the reference impedance, use the and keys to select the numeric po- sition. then use the and keys to select the desired value. be sure to press enter after changing the reference impedance. notes dbm is valid for positive and negative values of dc volts. the mx+b and percent math operations are applied after the dbm or db math. for example, if mx+b is selected with m=10 and b=0, the display will read 10.000 mxb for a 1vdc signal. if dbm is selected with z ref = 50 ? , the display will read 130mxb. dbm = 10 log v 2 in /z ref ?? ?? 1mw -------------------------------- - 2-32 basic measurements db calculation expressing dc or ac voltage in db makes it possible to compress a large range of measure- ments into a much smaller scope. the relationship between db and voltage is de ned by the following equation: where: v in is the dc or ac input signal. v ref is the speci ed voltage reference level. the instrument will read 0db when the reference voltage level is applied to the input. if a relative value is in effect when db is selected, the value is converted to db then rel is applied to db. if rel is applied after db has been selected, db has rel applied to it. con?uration to set the reference voltage, perform the following steps: 1. after selecting db, the present reference voltage level is displayed: ref: +0.000000 2. to change the reference level, use the and keys to select the numeric position. then use the and keys to select the desired value. be sure to press enter after changing the reference voltage. notes the db calculation takes the absolute value of the ratio v in / v ref the largest negative value of db is -160db. this will accommodate a ratio of v in = 1? and v ref = 1000v. db= 20 log v in v ref ----------------- - basic measurements 2-33 measuring continuity the model 2000 uses the 1k ? range to measure circuit continuity. after selecting continuity, the unit prompts you for a threshold resistance level (1 ? -1000 ? ). the model 2000 alerts you with a beep when a reading is below the set level. to measure the continuity of a circuit, press shift then cont, set the threshold resistance level and connect the circuit. note continuity has a non-selectable reading rate of fast (0.1 plc). connections connect the circuit you want to test to the input hi and input lo terminals of the model 2000. the test current ows from the input hi as shown in figure 2-9. threshold resistance level you can de?e a threshold resistance from 1 ? to 1000 ? . the factory setting is 10 ? . follow these steps to de ne the resistance level: 1. press shift then cont. 2. use the and keys to choose a numerical place and use the and keys to in- crement or decrement the digits. enter a value from 1 to 1000. 3. press enter to con rm your setting. 2001 multimeter model 2000 resistance under test note: source current flows from the input hi to input lo terminals. shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err 2-34 basic measurements figure 2-9 continuity mea- surements testing diodes with a model 2000, you can measure the forward voltage drop of general-purpose diodes and the zener voltage of zener diodes. to test diodes, press shift then , set the test current range, connect the diode, and take a reading from the display. note diode test has a non-selectable reading rate of medium (1 plc). connections connect the diode leads to the input hi and input lo terminals on the model 2000. the test current ows from the input hi terminal as shown in figure 2-10. range you can set the test current range from the front panel. the choices are 1ma, 100?, and 10?. the factory test current setting is 1ma. to set the test current, do following: 1. press shift then . 2. use the and keys to scroll through the three test current selections. the diode test measures voltages on the 3v range for the 1ma test current and the 10v range for the 100? and 10? ranges. if a reading is more than 10v, the model 2000 displays the ?verflow?status message. 2001 multimeter model 2000 general-purpose diode shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err 2001 multimeter model 2000 zener diode shift ch1 rem talk lstn srq stat rel filt 4w buffer math rear scan timer step ch2 ch3 ch4 ch5 ch6 ch7 ch 8 ch9 ch1 0 hold trig fast med slow auto err note: source current flows from the input hi to input lo terminals. basic measurements 2-35 figure 2-10 diode testing 2-36 basic measurements 3 measurement options introduction this section describes the front panel features of the model 2000. for those measurement op- tions accessible only by a remote interface, refer to sections 4 and 5. this section is organized as follows: measurement con guration describes ranging, ltering, relative readings, digits of resolution, and measurement rate. trigger operations uses a trigger model to explain trigger modes and sources. buffer operations discusses the reading storage buffer and buffer statistics. limit operations de?es how to set reading limits. scan operations explains the internal and external scanning capabilities. system operations gives details on setup saving and restoring, selecting a remote in- terface, and accessing test and calibration. 3-2 measurement options measurement con?uration the following paragraphs discuss con guring the multimeter for making measurements. see the end of appendix a for information about optimizing readings for speed or accuracy. range the selected measurement range affects both the ultimate digits and accuracy of the measure- ments as well as the maximum signal that can be measured. the range setting ( xed or auto) for each measurement function is saved when changing functions. maximum readings the full scale readings for every range on each function are 20% overrange except for the 1000vdc, 750vac, 3adc, 3aac, and diode test ranges. input values more than the maximum readings cause the "overflow" messages to be dis- played. manual ranging to select a range, simply press the range or key. the instrument changes one range per keypress. the selected range is displayed for one second. if the instrument displays the "overflow" message on a particular range, select a higher range until an on-range reading is displayed. use the lowest range possible without causing an over?w to ensure best accuracy and resolution. note that the temperature and continuity functions have just one range. autoranging to enable autoranging, press the auto key. the auto annunciator turns on when autorang- ing is selected. while autoranging is selected, the instrument automatically chooses the best range to measure the applied signal. autoranging should not be used when optimum speed is required. note that up-ranging occurs at 120% of range, while down-ranging occurs at 10% of nominal range. to cancel autoranging, press auto or the range or key. pressing auto to cancel autoranging leaves the instrument on the present range. the auto key has no effect on the temperature, continuity, and diode test functions. measurement options 3-3 filter filter lets you set the lter response to stabilize noisy measurements. the model 2000 uses a digital ?ter, which is based on reading conversions. the displayed, stored, or transmitted read- ing is simply an average of a number of reading conversions (from 1 to 100). to select a ?ter: 1. press filter once if the filt annunciator is off; press twice if filt is on. 2. enter the number of readings. 3. select the type of lter you want (moving average or repeating), then press enter. the filt annunciator turns on. when a ?ter is enabled, the selected lter con?uration for that measurement function is in effect. pressing filter once disables the lter. note the ?ter can be set for any measurement function except frequency, period, continu- ity, and diode test. filter types the moving average ?ter uses a ?st-in, ?st-out stack. when the stack becomes full, the measurement conversions are averaged, yielding a reading. for each subsequent conversion placed into the stack, the oldest conversion is discarded, and the stack is re-averaged, yielding a new reading. for the repeating lter, the stack is lled and the conversions are averaged to yield a reading. the stack is then cleared and the process starts over. choose this ?ter for scanning so readings from other channels are not averaged with the present channel. conversion #10 #9 #8 #7 #6 #5 #4 #3 #2 conversion #1 reading #1 a. type - moving average, readings = 10 conversion #11 #10 #9 #8 #7 #6 #5 #4 #3 conversion #2 reading #2 conversion #12 #11 #10 #9 #8 #7 #6 #5 #4 conversion #3 reading #3 conversion #10 #9 #8 #7 #6 #5 #4 #3 #2 conversion #1 reading #1 b. type - repeating, readings = 10 conversion #20 #19 #18 #17 #16 #15 #14 #13 #12 conversion #11 reading #2 conversion #30 #29 #28 #27 #26 #25 #24 #23 #22 conversion #21 reading #3 3-4 measurement options figure 3-1 moving average and repeating fil- ters response time the ?ter parameters have speed and accuracy tradeoffs for the time needed to display, store, or output a ?tered reading. these affect the number of reading conversions for speed versus ac- curacy and response to input signal changes. relative the rel (relative) function can be used to null offsets or subtract a baseline reading from present and future readings. when rel is enabled, the instrument uses the present reading as a relative value. subsequent readings will be the difference between the actual input value and the rel value. you can de?e a rel value for each function. once a rel value is established for a measurement function, the value is the same for all ranges. for example, if 50v is set as a rel value on the 100v range, the rel is also 50v on the 1000v, 10v, 1v, and 100mv ranges. thus, when you perform a zero correction for dcv, ? 2, and ? 4 measurements by enabling rel, the displayed offset becomes the reference value. subtracting the offset from the actual input zeroes the display, as follows: actual input ?reference = displayed reading a rel value can be as large as the highest range. selecting a range that cannot accommodate the rel value does not cause an over?w condi- tion, but it also does not increase the maximum allowable input for that range. for example, on the 10v range, the model 2000 still over?ws for a 12v input. to set a rel (relative) value, press rel key when the display shows the value you want as the relative value. the rel annunciator turns on. pressing rel a second time disables rel. you can input a rel value manually using the mx+b function. set m for 1 and b for any value you want. pressing rel enables that value to be the relative value. see section 2 for more information on the mx+b function. digits the display resolution of a model 2000 reading depends on the digits setting. it has no ef- fect on the remote reading format. the number of displayed digits does not affect accuracy or speed. those parameters are controlled by the rate setting. perform the following steps to set digits for a measurement function: 1. press the desired function. 2. press the digits key until the desired number of digits is displayed (3 ? to 6 ? ). note frequency and period can be displayed with four to seven digits. measurement options 3-5 rate the rate operation sets the integration time of the a/d converter, the period of time the in- put signal is measured (also known as aperture). the integration time affects the usable digits, the amount of reading noise, as well as the ultimate reading rate of the instrument. the integra- tion time is speci ed in parameters based on a number of power line cycles (nplc), where 1 plc for 60hz is 16.67msec and 1 plc for 50hz and 400hz is 20msec. in general, the fastest integration time (fast (0.1 plc) from the front panel, 0.01 plc from the bus) results in increased reading noise and fewer usable digits, while the slowest integration time (10 plc) provides the best common-mode and normal-mode rejection. in-between settings are a compromise between speed and noise. the rate parameters are explained as follows: fast sets integration time to 0.1 plc. use fast if speed is of primary importance (at the expense of increased reading noise and fewer usable digits). medium sets integration time to 1 plc. use medium when a compromise between noise performance and speed is acceptable. slow sets integration time to 10 plc. slow provides better noise performance at the expense of speed. note the integration time can be set for any measurement function except frequency, peri- od, continuity (fast), and diode test (medium). for frequency and period, this value is gate time or aperture. for the ac functions, medium and slow have no effect on the number of power line cycles. see the discussion on ?andwidth?that follows. 3-6 measurement options bandwidth the rate setting for ac voltage and current measurements determines the bandwidth setting: slow ?3hz to 300khz. medium ?30hz to 300khz. fast ?300hz to 300khz. bandwidth is used to specify the lowest frequency of interest. when the slow bandwidth (3hz to 300khz) is chosen, the signal goes through an analog rms converter. the output of the rms converter goes to a fast (1khz) sampling a/d and the rms value is calculated from 1200 digitized samples (1.2s). when the medium bandwidth (30hz to 300khz) is chosen, the same circuit is used. however, only 120 samples (120ms) are needed for an accurate calculation because the analog rms con- verter has turned most of the signal to dc. in the fast bandwidth (300hz to 300khz), the output of the analog rms converter (nearly pure dc at these frequencies) is simply measured at 1 plc (16.6ms). table 3-1 lists the rate settings for the various measurement functions. the fast, med, and slow annunciators are only lit when conditions in the table are met. in other case, the annun- ciators are turned off. table 3-1 rate settings for the measurement functions function rate fast medium slow dcv, dci acv, aci ? 2w, ? 4w freq, period db, dbm (acv) db, dbm (dcv) continuity diode test nplc=0.1 nplc=1, bw=300 nplc=0.1 aper=1s nplc=1, bw=300 nplc=0.1 nplc=0.1 n/a nplc=1 nplc=x, bw=30 nplc=1 aper=1s nplc=x, bw=30 nplc=1 n/a nplc=1 nplc=10 nplc=x, bw=3 nplc=10 aper=1s nplc=x, bw=3 nplc=10 n/a n/a notes: nplc = number of power line cycles. bw = lower limit of bandwidth (in hz). aper = aperture in seconds. n/a = not available. x = setting ignored. measurement options 3-7 trigger operations the following paragraphs discuss front panel triggering, the programmable trigger delay, the reading hold feature, and external triggering. trigger model the ?wchart of figure 3-2 summarizes triggering as viewed from the front panel. it is called a trigger model because it is modeled after the scpi commands used to control triggering. note that for stepping and scanning, the trigger model has additional control blocks. these are de- scribed in ?can operations?later in this section. idle the instrument is considered to be in the idle state whenever it is not performing any mea- surements or scanning functions. from the front panel, the unit is considered idle at the end of a step or scan operation when the reading for the last channel remains displayed. to restore trig- gers, use the shift-halt keys. once the model 2000 is taken out of idle, operation proceeds through the owchart. control source and event detection the control source holds up operation until the programmed event occurs and is detected. the control sources are described as follows: immediate ?with this control source, event detection is immediately satis ed allowing operation to continue. external ?event detection is satis ed for any of three conditions: an input trigger via the trigger link line ext trig is received. a bus trigger (get or *trg) is received. the front panel trig key is pressed. (the model 2000 must be taken out of remote before it will respond to the trig key. use the local key or send local 716 over the bus.) idle control source immediate external event detection delay device action output trigger figure 3-2 front panel trig- gering without stepping/scanning 3-8 measurement options delay a programmable delay is available after event detection. it can be set manually or an auto de- lay can be used. with auto delay, the model 2000 selects a delay based on the function and range. the auto settings are listed in table 3-2. the delay function is accessed by pressing the shift-delay keys. the present delay set- ting (auto or manual) is displayed. use the and keys to select the type of delay. if manual is chosen, also enter the duration of the delay. the maximum is shown following: 99h:99m:99.999s press enter to accept the delay or exit for no change. changing the delay to manual on one function changes the delays on all functions to man- ual. table 3-2 auto delay settings function range and delay dcv acv freq 100mv 1ms 100mv 400ms 100mv 1ms 1v 1ms 1v 400ms 1v 1ms 10v 1ms 10v 400ms 10v 1ms 100v 5ms 100v 400ms 100v 1ms 1000v 5ms 750v 400ms 750v 1ms dci aci 10ma 2ms 100ma 2ms 1a 2ms 1a 400ms 3a 2ms 3a 400ms ? 2w, ? 4w continuity diode testing 100 ? 3ms 1k ? 3ms 1k ? 3ms 1ma 1ms 10k ? 13ms 100 a 1ms 100k ? 25ms 10 a 1ms 1m ? 100ms 10m ? 150ms 100m ? 250ms measurement options 3-9 device actions the primary device action is a measurement. however, the device action block could include the following additional actions: filtering ?if the repeating lter is enabled, the instrument samples the speci ed num- ber of reading conversions to yeildl single ltered reading. only one reading conversion is performed if the lter is disabled, or after the speci ed number of reading conversions for a moving average ?ter is reached. the output of lter feeds hold. hold ?with hold enabled, the rst processed reading becomes the ?eed?reading and operation loops back within the device action block. after the next reading is processed, it is checked to see if it is within the selected window (0.01%, 0.1%, 1%, 10%) of the ?eed?reading. if the reading is within the window, operation again loops back within the device action block. this looping continues until the speci ed number (2 to 100) con- secutive readings are within the window. if one of the readings is not within the window, the instrument acquires a new ?eed?reading and the hold process continues. channel closure ?when stepping or scanning, the last device action is to open the pre- vious channel (if closed) and close the next channel. using the hold feature provides an auto settling time for the scanner relays. each open/close transition will restart the hold process and a reading for each channel will not occur until the relay settles. output trigger after the device action, an output trigger occurs and is available at the rear panel trigger link connector. this trigger can be used to trigger another instrument to perform an operation (e.g., select the next channel for an external scan). counters the trigger model for stepping and scanning contains additional blocks for counting samples (the number of channels to scan) and counting triggers. these counters are explained in the para- graph ?can operations?later in this section. reading hold (autosettle) when a hold reading is acquired as described in ?evice actions? an audible beep is sounded (if enabled) and the reading is considered a ?rue measurement? the reading is held on the dis- play until an ?ut of window?reading occurs to restart the hold process. when operating remotely or scanning, the hold process seeks a new ?eed"?nce it has been satis?d and the reading has been released. when operating from the front panel, the hold pro- cess does not seek a new "seed" until the held condition is removed. 3-10 measurement options hold example 1. enable hold, select a window percentage and enter a count. 2. apply test probes to a signal. once the signal becomes stable enough to satisfy the hold condition, the reading is released, and the beeper sounds (if enabled). 3. remove the hold condition by lifting the probes. hold will then seek a new ?eed? external triggering the ext trig key selects triggering from two external sources: trigger link and the trig key. when ext trig is pressed, the trig annunciator lights and dashes are displayed to indi- cate that instrument is waiting for an external trigger. from the front panel, you can press the trig key to trigger a single reading. pressing the ext trig key again toggles you back to con- tinuous triggers. the model 2000 uses two lines of the trigger link rear panel connector as external trigger (ext trig) input and voltmeter complete (vmc) output. the ext trig line allows the mod- el 2000 to be triggered by other instruments. the vmc line allows the model 2000 to trigger other instruments. at the factory, line 1 is con gured as vmc and line 2 as ext trig. (changing this con g- uration is described in the optional model 2000 repair manual.) a connector pinout is shown in figure 3-3. rear panel pinout 1 2 3 4 5 6 7 8 pin 2 external trigger input pin 1 voltmeter complete output pin number description 1 2 3 4 5 6 7 8 voltmeter complete output external trigger input no connection * signal ground no connection * no connection * no connection * signal ground * either pin 3 or 5 may be configured as an output instead of pin 1. either pin 4 or 6 may be configured as an input instead of pin 2. see the optional model 2000 repair manual for details. figure 3-3 rear panel pinout measurement options 3-11 external trigger the ext trig input requires a falling-edge, ttl-compatible pulse with the speci cations shown in figure 3-4. in general, external triggers can be used to control measure operations. for the model 2000 to respond to external triggers, the trigger model must be con gured for it. voltmeter complete the vmc output provides a ttl-compatible output pulse that can be used to trigger other instruments. the speci?ations for this trigger pulse are shown in figure 3-5. typically, you would want the model 2000 to output a trigger after the settling time of each measurement. external triggering example in a typical test system, you may want to close a channel and then measure the dut connect- ed to the channel with a multimeter. such a test system is shown in figure 3-6, which uses a model 2000 to measure ten duts switched by a model 7011 multiplexer card in a model 7001/ 7002 switch system. triggers on leading edge ttl high (2v-5v) ttl low ( 0.8v) 2s minimum meter complete ttl high (3.4v typical) ttl low (0.25v typical) 10s minimum figure 3-5 trigger link out- put pulse specifi- cations (vmc) 3-12 measurement options figure 3-4 trigger link input pulse specifica- tions (ext trig) the trigger link connections for this test system are shown in figure 3-7. trigger link of the model 2000 is connected to trigger link (either in or out) of the model 7001/7002. note that with the default trigger settings on the model 7001/7002, line #1 is an input and line #2 is an output. this complements the trigger lines on the model 2000. for this example, the model 2000 and 7001/7002 are con gured as follows: model 2000: factory defaults restored (accessed from shift-setup) external scanning, channels 1 - 10, no timer, 10 readings (accessed from shift-config) external triggers (accessed from ext trig) model 7001 or 7002: factory defaults restored scan list = 1!1-1!10, number of scans = 1 channel spacing = triglink to run the test and store readings in the model 2000 with the unit set for external triggers, press step or scan. the model 2000 waits (with the asterisk annunciator lit) for an external trigger from the model 7001/7002. 2000 multimeter 2000 multimeter 1 dut #1 2 dut #2 10 dut #10 output card 1 7011 mux card warning: no internal operator servicable parts,service by qualified personnel only. warning: no internal operator servicable parts,service by qualified personnel only. caution: for continued protection against fire hazard,replace fuse with same type and rating. caution: for continued protection against fire hazard,replace fuse with same type and rating. rs232 1 3 5 2 4 6 vmc ext trig fuse line 250mat (sb) 100 vac 120 vac 125mat (sb) 220 vac 240 vac 120 made in u.s.a. input 500v peak 350v peak 1000v peak trigger link sense ? 4w hi lo ! line rating 50, 60 400hz 17 va max ieee-488 (change ieee address from front panel) ! ! ! warning: no internal operator servicable parts,service by qualified personnel only. warning: no internal operator servicable parts,service by qualified personnel only. caution: for continued protection against fire hazard,replace fuse with same type and rating. caution: for continued protection against fire hazard,replace fuse with same type and rating. made in usa 7001 or 7002 switch system 2000 multimeter trigger link trigger link cable (8501) trigger link out in figure 3-7 trigger link con- nections measurement options 3-13 figure 3-6 dut test system press step on the model 7001/7002 to take it out of idle and start the scan. the scanner's output pulse triggers the model 2000 to take a reading, store it, and send a trigger pulse. the following explanation on operation is referenced to the operation model shown in figure 3-8. idle bypass b wait for trigger link trigger scan channel c output trigger trigger d no scanned 10 channels ? yes 7001or 7002 make measurement made 10 measurements ? 2000 press step to start scan a wait for trigger link trigger e output trigger trigger f no yes idle figure 3-8 operation model for triggering ex- ample 3-14 measurement options pressing ext trig then step or scan on the multimeter places it at point a in the ?wchart, where it is waiting for an external trigger. pressing step takes the model 7001/7002 out of the idle state and places operation at point b in the owchart. for the ?st pass through the model, the scanner does not wait at point b for a trigger. instead, it closes the rst channel. after the relay settles, the model 7001/7002 outputs a channel ready pulse. since the instrument is programmed to scan ten channels, operation loops back up to point b, where it waits for an input trigger. and remember that the model 2000 operation is at point a waiting for a trigger. the output channel ready pulse from the model 7001/7002 triggers the multimeter to measure dut #1 (point e). after the measurement is complete, the model 2000 outputs a completion pulse (point f) and then loops back to point a, where it waits for another input trigger. the trigger applied to the model 7001/7002 from the model 2000 closes the next channel in the scan. this triggers the multimeter to measure the next dut. the process continues until all ten channels are scanned and measured. a b c d e f measurement options 3-15 external triggering with bnc connections an adapter cable is available to connect the micro-din trigger link of the model 2000 to instruments with bnc trigger connections. the model 8503 din to bnc trigger cable has a micro-din connector at one end and two bnc connectors at the other end. the bnc cables are labeled vmc (trigger line 1) and ext trig (trigger line 2). figure 3-9 shows how a keithley model 706 scanner can be connected to the trigger link of the model 2000 using the adapter cable. with this adapter, a model 706 could be substituted for the model 7001/7002 in the previous example. with the model 706 set for external trigger- ing, the test would start when the single scan mode is selected and initiated. if the model 2000 trigger line con guration has been changed from the factory setting, the model 8502 trigger link adapter must be used to interface with instruments having bnc trig- ger connections. it has two micro-din connectors and six bnc connectors, one for each trigger line. warning: no internal operator servicable parts,service by qualified personnel only. warning: no internal operator servicable parts,service by qualified personnel only. caution: for continued protection against fire hazard,replace fuse with same type and rating. caution: for continued protection against fire hazard,replace fuse with same type and rating. rs232 1 3 5 2 4 6 vmc ext trig fuse line 250mat (sb) 100 vac 120 vac 125mat (sb) 220 vac 240 vac made in u.s.a. input 500v peak 350v peak 1000v peak trigger link sense w 4w hi lo ! line rating 50, 60 400hz 17 va max ieee-488 (change ieee address from front panel) ! ! ! keithley 2000 multimeter 706 scanner channel ready external trigger model 8503 din to bnc trigger cable figure 3-9 din to bnc trig- ger cable 3-16 measurement options buffer operations the model 2000 has a buffer to store from two to 1024 readings and units. it also stores the channel number for scanned readings and over?w readings. in addition, recalled data includes statistical information, such as minimum, maximum, average, and standard deviation. the buffer ?ls with the requested number of readings and stops. readings are placed in the buffer after any math operations are performed. buffered data is overwritten each time the stor- age operation is selected. the data is volatile; it is not saved through a power cycle. the following paragraphs discuss storing and recalling buffered data. storing readings use the following procedure to store readings: 1. set up the instrument for the desired con guration. 2. press the store key. 3. using the , , , and keys to select the number of readings desired. 4. press enter. the asterisk (*) annunciator turns on to indicate a data storage operation. it will turn off when the storage is nished. measurement options 3-17 recalling readings use the following steps to view stored readings and buffer statistics: 1. press recall. the buffer annunciator indicates that stored readings are being dis- played. the arrow annunciator indicates that more data can be viewed with the , , , and keys. 2. as shown in figure 3-10, use the cursor keys to navigate through the reading numbers, reading values, and statistics. for any of the buffer statistics (maximum, minimum, av- erage, statndard deviation), the stat annunciator is on. 3. use the exit key to return to the normal display. rdg no. 10 reading value rdg no. 9 reading value rdg no. 8 reading value rdg no. 7 reading value rdg no. 6 reading value rdg no. 5 reading value rdg no. 4 reading value rdg no. 3 reading value rdg no. 2 reading value rdg no. 1 reading value std dev standard deviation value average average value min at xx minimum value max at xx maximum value range range figure 3-10 buffer locations 3-18 measurement options buffer statistics the max at and min at values are the maximum and minimum values in the buffer. the average value is the mean of the buffered readings. the equation used to calculate the mean is: where: x i is a stored reading n is the number of stored readings the std dev value is the standard deviation of the buffered readings. the equation used to calculate the standard deviation is: where: x i is a stored reading n is the number of stored readings note the model 2000 uses ieee-754 oating point format for math calculations. y x i i1 = n n ----------------- = x 2 i i1 = n 1 n -- -x i i1 = n ?? ?? ?? ?? 2 ?? ?? ?? ?? n-1 -------------------------------------------------------------- y = measurement options 3-19 limit operations limit operations set and control the values that determine the hi / in / lo status of subse- quent measurements. limits can be applied to all measurement functions except continuity. the limit test is performed after mx+b and percent math operations. unit pre xes are applied before the limit test, for example: low limit = -1.0, high limit = 1.0 a 150mv reading equals 0.15v (in). low limit = -1.0, high limit = 1.0 a 0.6k ? reading equals 600 ? (hi). you can con?ure the multimeter to beep or not when readings are inside or outside of the limit range. setting limit values use the following steps to enter high and low limit values: 1. press the shift-limits keys to view the present hi limit value: hi:+1.000000 ^ this value represents the absolute value of that function. 2. use the , , , and keys to enter the desired value. move the cursor to the right- most position and use the and keys to move the decimal point. 3. press enter to view the present lo limit value: lo:-1.000000 ^ this value represents the absolute value of that function. 4. enter the desired value for the low limit. pressing enter returns to the normal display. 3-20 measurement options enabling limits use the following procedure to turn on the limits operation: 1. press the shift-on/off keys to view the present beeper status: beep: never 2. use the and keys to change the beeper status (never, outside, inside). press enter when done. when the multimeter returns to the normal display, the hi/in/lo status is displayed along with the reading. to disable limit testing, press shift-on/off again. an example of using lim- its to sort resistors is shown in figure 3-11. lo in hi 90 ? lo limit 110 ? hi limit figure 3-11 using limit test to sort 100 ? , 10% resistors measurement options 3-21 scan operations the model 2000 can be used with an internal scanner card (model 2000 scan or 2001-tcs- can) or with external scanner cards installed in switching mainframes such as the models 707, 7001, and 7002. the following paragraphs discuss various aspects of using scanning with the model 2000. connection precautions warnings connection information for scanner cards is intended for quali ed service personnel. do not attempt to connect the dut or external circuitry to a scanner card unless quali ed to do so. to prevent electric shock that could result in serious injury or death, adhere to the following safety precautions: before making or breaking connections to the scanner card, make sure the model 2000 power is turned off and power is removed from all external circuitry. do not connect signals that will exceed the maximum speci cations of the scanner card. if both the front panel terminals and the scanner card terminals are con- nected at the same time, the maximum signal ratings of the front panel ter- minals are reduced to the maximum signal ratings of the scanner card. as described in the international electrotechnical commission (iec) stan- dard iec 664, scanner cards are installation category i and must not be connected to mains. scanning overview a scanner lets you switch among a number of input signals to the model 2000 for measure- ment. the channel control and scanning capabilities depend on whether an internal or external card is being used, as well as on the capabilities of the scanner card. refer to the documentation supplied with the scanner card for speci c connection information. using an internal scanner card the optional model 2000-scan scanner card lets you step through or scan up to ten 2-pole channels or ?e 4-pole channels. the optional model 2001-tcscan thermocouple/general purpose scanner card lets you multiplex one of nine 2-pole or one of four 4-pole analog signals into the model 2000, and/or any combination of 2- or 4-pole analog signals. using external scanner cards when using external channels, the switching mainframe controls the opening and closing of individual channels. to synchronize model 2000 measurements with external channel closures, connect the trigger link lines of the multimeter and switching mainframe. refer to ?rigger op- erations?earlier in this section for details and an example on using external triggering. 3-22 measurement options front panel scanner controls in addition to the trigger keys discussed previously, front panel keys that affect scanner card operation include: and ?allow you to manually step through consecutive internal card channels. open and close ?let you selectively open and close internal card channels. shift-config ?selects internal or external scanning, scan list, time between scans, and reading count. step ?starts a stepping operation of consecutive channels, where output triggers are sent after every channel closure. scan ?starts a scanning operation of consecutive channels, where an output trigger is sent at the end of the scan list. shift-halt ?stops stepping or scanning and restores the trigger model to a non- scanning mode. using and keys the and keys can be used to manually scan through channels on the internal scanner card. with a scanner card installed in the option slot, press the key to manually increment channels or the key to manually decrement channels. the annunciator of the closed channel is lit. hold down either key to manually scan through channels continuously. press open to open all channels. using open and close keys the open and close keys control channels on the internal scanner card only. the keys allow you to directly: close a speci c channel (or channel pair for 4-wire resistance). immediately open any internal closed channel (or channel pair for 4-wire resistance). with a scanner card installed in the option slot of the model 2000, the following prompt is displayed when the close key is pressed: close chan:01 use the , , , and keys to display the desired channel (1 to 10) and press enter. the annunciator of the closed channel will be displayed on the front panel along with normal readings. selecting a different channel from the one that is presently closed will cause the closed channel to open and allow a settling time before closing the selected channel. channel relays will be closed according to the presently selected function. if a 4-wire func- tion is selected, both the selected channel relay and the matching relay pair will be closed. fixed 4-pole relay pairs are: 1 and 6 (not available for model 2001-tcscan) 2 and 7 3 and 8 4 and 9 5 and 10 pressing the open key will immediately open any closed scanner card channel or channel pair for 4-wire resistance. measurement options 3-23 stepping and scanning trigger model additions the trigger model presented in ?rigger operations?earlier in this section has some addition- al capabilities when stepping or scanning. these are outlined below: timer ?with this control source, event detection is immediately satis ed on the initial pass. each subsequent detection is satis ed when the programmed timer interval (up to 99h:99m:99.99s) elapses. reading counter ?for both stepping and scanning, the reading count can be entered from shift-config. (this is referred to as the trigger counter over the bus.) the read- ing counter can bypass the idle state. operation will wait until the programmed control source event occurs. channel counter ?for scanning, the scan list length (maximum channel less minimum channel) is used to bypass the control source allowing a speci?d number of device ac- tions to occur. (this counter is referred to as the sample counter over the bus.) these additional blocks are shown in the trigger models of figures 3-12 and 3-13. uses of the timer control source, reading counter, and channel counter are shown in the scanning exam- ples later in this section. idle control source immediate external timer event detection delay device action output trigger more readings ? reading count (trigger counter) yes no figure 3-12 front panel trig- gering with step- ping 3-24 measurement options idle control source immediate external timer event detection delay device action output trigger more readings ? reading count (trigger counter) yes no more channels ? yes no scan list length (sample counter) figure 3-13 front panel trig- gering with scan- ning measurement options 3-25 using shift-config to con gure stepping and scanning from the shift-config key combination, you can select internal or external scanning, the minimum and maximum channels in the scan list, the time between scans, and the reading count. 1. to con?ure stepping or scanning, perform the following: 2. select the desired measurement function. 3. press the shift-config keys to access the step/scan con guration. 4. select the type of scan (internal or external) by using the and keys and pressing enter. 5. select the ?st channel in the scan list (minimum channel) by using the , , , and keys and pressing enter. 6. select the last channel in the scan list (maximum channel) and press enter to con- ?m. 7. the next selection is for timed scans. (this is the timer control source in the trigger model.) it sets a user-speci?d interval for starting scans. if you choose timed scans, the model 2000 prompts for a time interval: 00h:00m:00.000s use the , , , and keys to select a time interval and press enter to con rm. 8. next, you are prompted for a reading count (rdg cnt). this can be less than, equal to, or greater than the scan list length (up to 1024). it is the number of readings that will be stored in the buffer. the effects of these choices are further described in the scanning ex- amples. 9. press enter when done to return to the normal display. note that scanned readings are always stored in the buffer, up to the setting for rdg cnt. 3-26 measurement options scanning examples the following examples demonstrate the use of reading count, timed scans, delay, and exter- nal scanning. counters one of the con guration options for stepping and scanning is the reading count. the example of figure 3-14 shows how different settings of rdg cnt affect these operations: with a reading count (0010) equal to the scan list length (10), a step operation consecu- tively closes ten channels and sends an output trigger after each channel. a scan opera- tion also consecutively closes ten channels but sends an output trigger only at the end of the scan. with a reading count (0020) greater than the scan list length (10), stepping yields 20 channel closures and 20 output triggers. scanning also goes through the scan list twice but sends an output trigger only at the end of each scan. with a reading count (0002) less than the scan list length (10), stepping yields two chan- nel closures and output triggers. scanning goes through the entire scan list and sends an output trigger but only two readings are stored. type: int min chan: 1 max chan: 10 timer? off rdg cnt: 0010 0002 0020 step 20 channel closures 20 output triggers scan 10 channel closures (x2) 2 output triggers recall 20 readings step 10 channel closures 10 output triggers scan 10 channel closures 1 output triggers recall 10 readings step 2 channel closures 2 output triggers scan 10 channel closures 1 output triggers recall 2 readings note: "factory setup" on the model 2000 is assumed. shift-config figure 3-14 internal scanning example with reading count op- tion measurement options 3-27 note if the reading count divided by the scan list length is not an integer, it is rounded up. for example, if the reading count is 15 and the scan list length is 10, there will be two output triggers for scanning. the differences between stepping and scanning counters for bus commands are summarized in table 3-3. timing another con?uration option for stepping and scanning is the timing of channel closures. the example of figure 3-15 shows how different settings of timer and delay affect these oper- ations. these are the timer control source and the delay block shown in the trigger models of figures 3-12 and 3-13. with the timer on and set to ve seconds and delay set to auto, channels are stepped through at ?e-second intervals with an output trigger after each closure. a scan opera- tion yields ten channels scanned immediately with an output trigger at the end of the scan. with the timer off and the delay set to manual for ve seconds, stepping and scanning through the channels is timed the same. the difference is in the number of output trig- gers, with stepping sending a trigger after each channel closure and scanning sending a trigger at the end of the scan. when using both the timer and delay parameters, the timer is not started until after the delay. for example, if the timer is two minutes and the delay is ten seconds, the timer is not started until 10sec after pressing scan. each successive scan will occur at 2:10.0, 4:10.0, etc. if the total delay time per scan is greater than or equal to the timer setting, the timer condition is already satis ed and, effectively, is ignored. table 3-3 bus commands parameters for stepping and scanning counters operation :sample:count :trigger:count step 1 reading count scan scan list length (reading count) / (scan list length) 3-28 measurement options type:int min chan: 1 max chan: 10 timer? timer? on 00h:00m:05.000s rdg cnt: 0010 step 10 channel closures at 5-second intervals 10 output triggers scan 10 channel closures 1 output trigger recall 10 readings rdg cnt: 0010 delay: man 00h:00m:05.000s step 10 channel closures at 5-second intervals 10 output triggers scan 10 channel closures at 5-second intervals 1 output trigger recalll 10 readings off on note: "factory setup" on the model 2000 is assumed. shift-config figure 3-15 internal scanning example with tim- er and delay op- tions measurement options 3-29 external scanning the example of figure 3-16 shows the front panel operations to con gure an external scan. the trigger and signal connections were shown previously in ?rigger operations? both instru- ment setups assume factory defaults. set the model 2000 for the desired measurement function. on the model 7001 switch system, enter a scan list of channels 1 to 10 on card 1. also on the model 7001, con gure the instrument for trigger link triggers and one scan of ten channels. on the model 2000 multimeter, con?ure an external scan of the rst ten channels. set the model 2000 for external triggers by pressing ext trig. the display will be dashes. press step or scan on the model 2000. the asterisk and step or scan annuncia- tor will light. press step on the model 7001 to start channel closures. after the scan, you can recall ten readings from the model 2000 buffer. note when using an external thermocouple scanner card and channel 1 as a reference, the model 2000 only recognizes channel 1 when a step or scan is performed. if using a model 7001 or 7002 to close channel 1 manually, the model 2000 will not interpret that channel as the reference junction without a step or scan operation. 1 2 3 4 5 6 7 3-30 measurement options model 7001 (from "reset setup") scan channels 1!1-1!10 configure scan chan-control channel-spacing triglink asynchronous chan-count 10 scan-control scan-count 1 model 2000 (from "factory setup") shift-config type:ext min chan: 001 max chan: 010 timer? off rdg cnt: 0010 enter ex trig step or scan step recall (10 readings) , , , exit 1 2 3 4 5 6 7 figure 3-16 external scanning example with model 7001 measurement options 3-31 system operations the model 2000 has other front panel operations. saving and restoring setup information is described in section 2 ?basic measurements. selecting the remote interface and language is covered in section 4 ?remote operation. self-test the test selections are used as diagnostic tools to isolate problems within the model 2000. information on using these test procedures is included in the optional model 2000 repair man- ual. calibration the cal selections are used to view the calibration date and next due date, to perform cali- bration, and to view the number of times calibration has been performed. some of the items are password-protected to prevent unintended changing of calibration constants. to view the calibration dates, press shift-cal. press enter at the dates prompt. the ?st date is the last time calibration was performed. the ndue date is the calibration due date. running calibration is password-protected. refer to the model 2000 calibration manual for details. to view the calibration count, press enter at the count prompt. 3-32 measurement options 4 remote operation introduction this section includes the following information: selecting an interface selecting a language rs-232 operation gpib bus operation and reference status structure trigger model (gpib operation) programming syntax common commands selecting an interface the model 2000 multimeter supports two built-in remote interfaces: gpib bus rs-232 interface you can use only one interface at a time. the factory interface selection is the gpib bus. you can select the interface only from the front panel. the interface selection is stored in non-volatile memory; it does not change when power has been off or after a remote interface reset. before you select a remote interface, consider the programming language you want to use. for more information about selecting programming languages, see this section. 4-2 remote operation rs-232 you can connect a controller to the rs-232 interface. some considerations for selecting the rs-232 interface are the following: you must de?e the baud rate, enable or disable software handshake xon/xof. you can only use the scpi programming language with the rs-232 interface. to select rs-232 as the remote interface, do the following: 1. access the rs-232 con guration by pressing shift then rs232. you see: rs232: off 2. move to the on/off selection by pressing the key. you see off selection blinking. 3. turn on the rs-232 interface by toggling the selection to on using the or key and press enter. you can exit the con?uration menu by pressing exit. for more information about the rs-232 interface, see section rs-232 operation. gpib bus the gpib bus is the ieee-488 interface. you must select a unique address for the model 2000 multimeter. the address is displayed when the multimeter is turned on. at the factory, the ad- dress is set to 16. since gpib is the interface selection de ned by the factory, only follow these steps to select the gpib interface if you have been previously using the rs-232 remote programming interface: 1. select the gpib option by pressing shift then gpib. you see: gpib: off 2. move to the on/off selection by pressing the key. you see off selection blinking slowly. 3. turn on the gpib interface by toggling the selection to on using the or key and press enter. turning off the rs-232 interface automatically selects gpib as the remote programming in- terface. remote operation 4-3 selecting a language choose one of three languages to program the model 2000 multimeter: scpi (signal oriented measurement commands) keithley models 196/199 digital multimeter fluke model 8840a/8842a digital multimeter the factory sets the language selection as scpi. you only can select a programming language from the front panel. the language selection is stored in non-volatile memory, which means it does not change when power has been off or after a remote interface reset. table 4-1 shows the languages supported by the two available interfaces: as you make your language selection, keep in mind that the language you select determines the remote operations allowed. to select a programming language, follow these steps: 1. access the gpib con guration options by pressing shift then gpib. you see gpib:on with gpib blinking. 2. select the language con guration option by pressing the enter key twice. you see: lang: scpi standard commands for programmable instruments (scpi) is fully supported by the gpib and rs-232 interfaces. always calibrate the model 2000 multimeter using the scpi language. keithley models 196/199 digital multimeter the model 2000 multimeter implements virtually all commands available in the keithley models 196/199 digital multimeter, except for the self-test and calibration commands. the com- mands are listed in appendix d. see the models 196/199 digital multimeter user manuals for more information about remote programming. fluke model 8840a/8842a digital multimeter the model 2000 multimeter implements virtually all commands available in the fluke mod- els 8840a and 8842a digital multimeter, except for the self-test and calibration commands. the commands are listed in appendix d. see the fluke user manual for more information about remote programming. remote operation 4-5 rs-232 operation sending and receiving data the rs-232 interface transfers data using 8 data bits, 1 stop bit, and no parity. make sure the controller you connect to the multimeter also uses these settings. you can break data transmissions by sending a ^c or ^x character string to the multimeter. this clears any pending operation and discards any pending output. selecting baud rate the baud rate is the rate at which the model 2000 multimeter and the programming terminal communicate. choose one these available rates: 19.2k 9600 4800 2400 1200 600 300 the factory selected baud rate is 4800. when you choose a baud rate, make sure that the programming terminal that you are connect- ing to the model 2000 multimeter can support the baud rate you selected. both the multimeter and the other device must be con gured for the same baud rate. to select a baud rate, follow these steps: 1. access the rs-232 con guration by pressing shift then rs232. you see: rs232: on (assuming you have already selected the rs-232 interface) 2. go to the baud rate eld by pressing the key. you see baud: selecting signal handshaking (?w control) signal handshaking between the controller and the instrument allows the two devices to com- municate to each other regarding being ready or not ready to receive data. the model 2000 does not support hardware handshaking ( ow control). software ?w control is in the form of x__on and x__off characters and is enabled when xonxoff is selected from the rs232 flow menu. when the input queue of the model 2000 becomes more than 3/4 full, the instrument issues an x_off command. the control program should respond to this and stop sending characters until the model 2000 issues the x_on, which it will do once its input buffer has dropped below half-full. the model 2000 recognizes x_on and x_off sent from the controller. an x_off will cause the model 2000 to stop outputting characters until it sees an x_on. incoming commands are processed after the rs-232 connections the rs-232 serial port can be connected to the serial port of a controller (i.e., personal com- puter) using a straight through rs-232 cable terminated with db-9 connectors. do not use a null modem cable . the serial port uses the transmit (txd), receive (rxd) and signal ground (gnd) lines of the rs-232 standard. it does not use the hardware handshaking lines cts and rts. figure 4-1 shows the rear panel connector for the rs-232 interface, and table 4-2 shows the pinout for the connector. if your computer uses a db-25 connector for the rs-232 interface, you will need a cable or adapter with a db-25 connector on one end and a db-9 connector on the other, wired straight through (not null modem). error messages see appendix b for rs-232 error messages. table 4-2 rs-232 connector pinout pin number description 1 2 3 4 5 6 7 8 9 no connection txd, transmit data rxd, receive data no connection gnd, signal ground no connection cts, clear to send 1 rts, ready to send 1 no connection 1 cts and rts signals are not used. rear panel connector 54321 9876 rs232 4-8 remote operation figure 4-1 rs-232 interface connector gpib bus operation and reference introduction this section contains information about connecting to and using the gpib (ieee-488) bus. the information is organized as follows: gpib bus standards gpib bus connections selecting the primary address quickbasic 4.5 programming general bus commands front panel gpib operation gpib bus standards the gpib bus is the ieee-488 instrumentation data bus with hardware and programming standards originally adopted by the ieee (institute of electrical and electronic engineers) in 1975. the model 2000 multimeter conforms to these standards: ieee-488-1987.1 ieee-488-1987.2 this standard de nes a syntax for sending data to and from instruments, how an instrument interprets this data, what registers should exist to record the state of the instrument, and a group of common commands. scpi 1991 (standard commands for programmable instruments) this standard de nes a command language protocol. it goes one step farther than ieee-488- 1987.2 and de nes a standard set of commands to control every programmable aspect of an in- strument. remote operation 4-9 gpib bus connections to connect the model 2000 multimeter to the gpib bus, use a cable equipped with standard ieee-488 connectors as shown in figure 4-2. to allow many parallel connections to one instrument, stack the connector. two screws are located on each connector to ensure that connections remain secure. current standards call for metric threads, which are identi ed with dark-colored screws. earlier versions had different screws, which were silver-colored. do not use these types of connectors on the model 2000 mul- timeter, because it is designed for metric threads. figure 4-3 shows a typical connecting scheme for a multi-unit test system. to avoid possible mechanical damage, stack no more than three connectors on any one unit. note to minimize interference caused by electromagnetic radiation, use only shielded ieee-488 cables. available shielded cables from keithley are models 7007-1 and 7007-2. instrument controller instrument instrument 4-10 remote operation figure 4-2 ieee-488 con- nector figure 4-3 ieee-488 con- nections to connect the model 2000 multimeter to the ieee-488 bus, follow these steps: 1. line up the cable connector with the connector located on the rear panel. the connector is designed so that it will t only one way. figure 4-4 shows the location of the ieee- 488 connector. 2. tighten the screws securely, making sure not to over tighten them. 3. connect any additional connectors from other instruments as required for your applica- tion. 4. make certain that the other end of the cable is properly connected to the controller. most controllers are equipped with an ieee-488 style connector, but a few may require a dif- ferent type of connecting cable. see your controllers instruction manual for information about properly connecting to the ieee-488 bus. note you can only have 15 devices connected to a ieee-488 bus, including the controller. the maximum cable length is either 20- meters or two meters times the number of de- vices, whichever is less. not observing these limits may cause erratic bus operation. warning: no internal operator servicable parts,service by qualified personnel only. warning: no internal operator servicable parts,service by qualified personnel only. caution: for continued protection against fire hazard,replace fuse with same type and rating. caution: for continued protection against fire hazard,replace fuse with same type and rating. rs232 1 3 5 2 4 6 vmc ext trig fuse line 250mat (sb) 100 vac 120 vac 125mat (sb) 220 vac 240 vac made in u.s.a. input 500v peak 350v peak 1000v peak trigger link sense w 4w hi lo ! line rating 50, 60 400hz 22 va max ieee-488 (change ieee address from front panel) ! ! ! keithley remote operation 4-11 figure 4-4 ieee-488 con- nector location selecting the primary address the model 2000 multimeter ships from the factory with a gpib address of 16. when the mul- timeter powers up, it momentarily displays the primary address. you can set the address to a val- ue of 0-30. do not assign the same address to another device or to a controller that are on the same gpib bus. usually controller addresses are 0 or 21, but see the controllers instruction manual for details. make certain that the address of the controller is the same as that speci ed in the controllers pro- gramming language. to change the primary address, follow these steps: 1. access the gpib con guration settings by pressing shift then gpib. you see: gpib:on , with gpib blinking 2. go to address choice by pressing the key. you see: addr:16 3. go to the numeric eld by pressing the key. 4. enter a new address from 0-30 by using the and ; press enter. 5. return to the main display by pressing exit. quickbasic 4.5 programming programming examples are written in microsoft quickbasic 4.5 using the keithley kpc- 488.2 (or capital equipment corporation) ieee interface and the hp-style universal language driver (cechp). install the universal language driver before any programming example can be run, the universal language driver must ?st be installed. to install the driver, from the dos prompt, enter this command: cechp if you include the cechp command in your autoexec.bat ?e, the driver will automat- ically be installed every time you turn on your computer. 4-12 remote operation about program fragments program fragments are used to demonstrate proper programming syntax. as the name im- plies, only a fragment of the whole program is used to avoid redundancy. at the beginning of each program, driver ?es have to be opened. the input terminator should be set for crlf. for example: open "ieee" for output as #1 open "ieee" for input as #2 print #1, "interm crlf" a typical program fragment includes an output command and an enter command. the output command sends a program message (command string) to the model 2000 multimeter. if the program message includes a query command, then the enter command is required to get the response message from the model 2000 multimeter. the enter command addresses the model 2000 multimeter to talk. the following example program fragment demonstrates how output and enter commands are used. note that the commands assume address 16, which is the factory-set address of the model 2000 multimeter. print #1, "output 16; :func 'volt:ac'; func?" print #1, "enter 16" if you wish to display the response message on the crt, the computer will have to read the message and then ?rint?it to the crt display as follows: line input #2, a$ print a$ the following programming example shows how all the above statements are used together. the program fragment is shown in bold typeface. open "ieee" for output as #1 'open driver open "ieee" for input as #2 'open driver print #1, "interm crlf" 'crlf terminator print #1, "output 16;:func 'volt:ac'; func?" 'select acv and query print #1, "enter 16" 'get response message line input #2, a$ 'read response message print a$ 'display message remote operation 4-13 general bus commands general bus commands and associated statements general commands are those commands, such as dcl, that have the same general meaning regardless of the instrument. table 4-3 lists the general bus commands along with the program- ming statement for each command, which use the keithley kpc-488.2 ieee interface and the hp- style universal language driver. note that the commands requiring that the primary ad- dress be speci ed assume that the address is the factory-set address of 16. ren (remote enable) the remote enable command is sent to the model 2000 by the controller to set up the instru- ment for remote operation. generally, the instrument should be placed in the remote mode be- fore you attempt to program it over the bus. simply setting ren true does not actually place the instrument in the remote state. you must address the instrument to listen after setting ren true before it goes into remote. note that the instrument need not be in remote to be a talker. program fragment print #1, "remote 16" 'place the model 2000 in remote; turn on rem annunciator note that all front panels controls except for local (and power) are inoperative while the instrument is in remote. you can restore normal front panel operation by pressing the local key. table 4-3 general bus commands and associated statements command programming statement effect on model 2000 multimeter ren ifc llo gtl dcl sdc get spe, spd remote 16 abort local lockout local 16 local clear clear 16 trigger 16 spoll 16 goes into effect when next addressed to listen. goes into talker and listener idle states. local key locked out. cancel remote; restore front panel operation for the 2000. cancel remote; restore front panel operation for all devices. return all devices to known conditions. returns model 2000 to known conditions. initiates a trigger. serial polls the model 2000. 4-14 remote operation ifc (interface clear) the ifc command is sent by the controller to place the model 2000 multimeter in the local, talker, listener idle states. the unit responds to the ifc command by canceling front panel talk or lstn lights, if the instrument was previously placed in one of those states. note that this command does not affect the status of the instrument; settings, data, and event registers are not changed. to send the ifc command, the controller need only set the ifc line true for a minimum of 100?. program fragment print #1, "output 16; *idn?" 'send query command print #1, "enter 16" 'read data; turn on talk annunci- ator sleep 3 'wait 3 seconds print #1, "abort" 'talker idle state; turn off talk annunciator llo (local lockout) use the llo command to prevent local operation of the instrument. after the unit receives llo, all its front panel controls except the power are inoperative. in this state, pressing the local will not restore control to the front panel. the gtl command restores control to the front panel. program fragment print #1, "remote 16" 'place 2000 in remote print #1, "local lockout" 'lock out front panel (including local key) sleep 6 'wait 6 seconds print #1, "local 16" 'restore front panel operation gtl (go to local) use the gtl command to put a remote-mode instrument into local mode. the gtl com- mand also restores front panel key operation. program fragment print #1, "remote 16" 'place 2000 in remote sleep 3 'wait 3 seconds print #1, "local 16" 'place 2000 in local mode remote operation 4-15 dcl (device clear) use the dcl command to clear the gpib interface and return it to a known state. note that the dcl command is not an addressed command, so all instruments equipped to implement dcl will do so simultaneously. when the model 2000 multimeter receives a dcl command, it clears the input buffer and output queue, cancels deferred commands, and clears any command that prevents the process- ing of any other device command. a dcl does not affect instrument settings and stored data. program fragment print #1, "clear" 'clear all devices sdc (selective device clear) the sdc command is an addressed command that performs essentially the same function as the dcl command. however, since each device must be individually addressed, the sdc com- mand provides a method to clear only selected instruments instead of clearing all instruments simultaneously, as is the case with dcl. program fragment print #1, "clear 16" 'clear 2000 4-16 remote operation get (group execute trigger) get is a gpib trigger that is used as an arm, scan and/or measure event to control operation. the model 2000 multimeter reacts to this trigger if it is the programmed control source. the control source is programmed from the scpi: trigger subsystem. with the instrument programmed and waiting for a gpib trigger, the following program frag- ment will provide the get: program fragment print #1, "trigger 16" 'trigger 2000 from over the bus this sends ieee-488 commands unt unl listen 16 get. when the command is execut- ed, the trigger event occurs. (the command trigger just sends get. any other listeners are triggered when the command is executed.) spe, spd (serial polling) use the serial polling sequence to obtain the model 2000 serial poll byte. the serial poll byte contains important information about internal functions, (see ?tatus structure?. generally, the serial polling sequence is used by the controller to determine which of several instruments has requested service with the srq line. however, the serial polling sequence may be performed at any time to obtain the status byte from the model 2000 multimeter. program fragment print #1, "spoll 16" 'serial poll the 2000 input #2, s 'read serial poll byte print s 'display the decimal value of the serial poll byte remote operation 4-17 front panel gpib operation this section describes aspects of the front panel that are part of gpib operation, including messages, status indicators, and the local key. error and status messages see section 2 for a list of error and status messages associated with ieee-488 programming. the instrument can be programmed to generate an srq, and command queries can be per- formed to check for speci c error conditions. gpib status indicators the rem (remote), talk (talk), lstn (listen), and srq (service request) annunciators show the gpib bus status. each of these indicators is described below. rem ?this indicator shows when the instrument is in the remote state. rem does not necessarily indicate the state of the rem line, as the instrument must be addressed to listen with rem true before the rem indicator turns on. when the instrument is in re- mote, all front panel keys, except for the local key, are locked out. when rem is turned off, the instrument is in the local state, and front panel operation is restored. talk ?this indicator is on when the instrument is in the talker active state. place the unit in the talk state by addressing it to talk with the correct mta (my talk address) command. talk is off when the unit is in the talker idle state. place the unit in the talker idle state by sending an unt (untalk) command, addressing it to listen, or sending the ifc (interface clear) command. lstn ?this indicator is on when the model 2000 multimeter is in the listener active state, which is activated by addressing the instrument to listen with the correct mla (my listen address) command. lstn is off when the unit is in the listener idle state. place the unit in the listener idle state by sending unl (unlisten), addressing it to talk, or send- ing ifc (interface clear) command over the bus. srq ?you can program the instrument to generate a service request (srq) when one or more errors or conditions occur. when this indicator is on, a service request has been generated. this indicator stays on until the serial poll byte is read or all the conditions that caused srq have ceased to exist. see ?tatus structure?for more information. local key the local key cancels the remote state and restores local operation of the instrument. pressing the local key also turns off the rem indicator and returns the display to normal if a user-de?ed message was displayed. if the llo (local lockout) command is in effect, the local key is also inoperative. 4-18 remote operation status structure see figure 4-5 for the model 2000 multimeters status structure. instrument events, such as errors, are monitored and manipulated by four status register sets. notice that these status regis- ter sets feed directly into the status byte register. more detailed illustrations of these register sets are provided by figures 4-5 through 4-9. 0 2 3 5 6 cal 7 9 10 11 12 13 14 15 questionable condition register (always zero) 0 2 3 5 6 7 9 10 11 12 13 14 15 questionable event register 0 11 1 2 3 5 6 7 9 10 11 12 13 14 15 questionable event enable register & & & & & & & & & & & & & & & & logical or 3 trig 7 8 idle 11 12 13 15 operation condition register (always zero) 3 7 8 idle 11 12 13 15 operation event register 3 7 8 idle 11 12 13 15 operation event enable register & & & & & & & & & & & & & & & & logical or idle eav qsb mav esb rqs/mss osb status byte register 1 eav qsb mav esb 6 osb service request enable register & & & & & & & logical or *stb? *sre *sre? master summary status (mss) msb = measurement summary bit eav = error available qsb = questionable summary bit mav = message available esb = event summary bit rqs/mss = request for service/master summary staus osb = operation summary bit error queue output queue trig trig note : rqs bit is in serial poll byte, mss bit is in *stb? response. 1 14 14 opc qye dde exe cme urq pon 8 9 8 11 12 13 15 standard event status register 8 9 8 11 12 13 15 standard event status enable register & & & & & & & & & & & & & & & & logical or (always zero) operation complete query error device specific error execution error command error user request power on opc qye dde exe cme urq pon *esr? *ese *ese? msb msb 12 13 14 15 (always zero) 12 13 14 15 measurement event register 12 13 14 15 measurement event enable register & & & & & & & & & & & & & & & & logical or measurement condition register rof ll hl 3 4 rav bav bhf bfl rof ll hl rav bav bhf bfl rof ll1 hl1 rav bav bhf bfl reading overfolw low limit high limit reading available buffer available buffer half full buffer full 11 cal cal calibration summary command warning warn warn warn 222 temperature summary temp temp temp 6 10 66 10 10 999 3 4 3 4 666 0 1 0 1 0 1 meas meas meas 11 11 11 measuring triggering remote operation 4-19 figure 4-5 model 2000 status register structure condition registers as figure 4-5 shows, all status register sets have a condition register. a condition register is a real-time, read-only register that constantly updates to re ect the current operating conditions of the instrument. for example, while a measurement is being performed, bit b4 (meas) of the operation condition register is set. when the measurement is completed, bit b4 clears. use the :condition? query commands in the status subsystem to read the condition reg- isters. see section 5 for more information. event registers as figure 4-5 shows, each status register set has an event register. an event register is a latched, read-only register whose bits are set by the corresponding condition register, once a bit in an event register is set, it remains set (latched) until the register is cleared by a speci c clearing operation. the bits of an event register are logically anded with the bits of the corresponding enable register and applied to an or gate. the output of the or gate is applied to the status byte register. use the *esr? common command to read the standard event register. all other event reg- isters are read using the :event? query commands in the status subsystem. see section 5 for more information. an event register is cleared when it is read. the following operations clear all event registers: cycling power sending *cls 4-20 remote operation enable registers as figure 4-5 shows, each status register set has an enable register. an enable register is pro- grammed by you and serves as a mask for the corresponding event register. an event bit is masked when the corresponding bit in the enable register is cleared (0). when masked, a set bit in an event register cannot set a bit in the status byte register (1 and 0 = 0). to use the status byte register to detect events (i.e., serial poll), you must unmask the events by setting (1) the appropriate bits of the enable registers. to program and query the standard event status register, use the *ese and *ese? common commands respectively. all other enable registers are programmed and queried using the :en- able and :enable? commands in the status subsystem. see section 5 for more information. an enable register is not cleared when it is read. the following operations affect the enable registers: cycling power - clears all enable registers :status:preset clears the following enable registers: operation event enable register questionable event enable register measurement event enable register *ese 0 - clears the standard event status enable register. remote operation 4-21 * esr ? pon (b7) urq (b6) cme (b5) exe (b4) dde (b3) qye (b2) (b1) (b0) or standard event status register standard event status enable register pon = power on urq = user request cme = command error exe = execution error dde = device-dependent error qye = query error opc = operation complete & = logical and or = logical or & & & & & opc & & pon (b7) urq (b6) cme (b5) exe (b4) dde (b3) qye (b2) (b1) (b0) opc * ese * ese ? to event summary bit (esb) of status byte register (see figure 4-10). (b15 - b8) (b15 - b8) or idle = idle state of the 2000 trig = triggering meas = measuring & = logical and or = logical or (b15 - b11) idle (b10) (b9) (b8) (b7) (b6) trig (b5) meas (b4) (b3) (b2) (b1) (b0) operation event register (b15 - b11) idle (b10) (b9) (b8) (b7) (b6) trig (b5) meas (b4) (b3) (b2) (b1) (b0) operation event enable register & to operation summary bit (osb) of status byte register. (see figure 4-10). & & (b15 - b11) idle (b10) (b9) (b8) (b7) (b6) trig (b5) meas (b4) (b3) (b2) (b1) (b0) operation condition register 4-22 remote operation figure 4-6 standard event status figure 4-7 operation event status or bfl = buffer full bhf = buffer half full bav = buffer available & = logical and or = logical or (b15 - b12) (b10) (b9) bhf (b8) bav (b7) (b6) rav (b5) (b4) (b3) (b2) ll (b1) (b0) measurement event register (b15 - b12) measurement event enable register to measurement summary bit (msb) of status byte register. (see figure 4-10) & & (b15 - b12) (b10) (b9) (b8) (b7) (b6) rav (b5) (b4) (b3) (b2) ll (b1) (b0) measurement condition register bfl hl rof bfl rof & & & bhf bav hl & & (b10) (b9) bhf (b8) bav (b7) (b6) rav (b5) (b4) (b3) (b2) ll (b1) (b0) bfl rof hl rav = reading available hl = high limit ll = low limit rof = reading overflow (b11) (b11) (b11) (b13 - b9) (b14) (b8) (b15) or questionable condition register questionable event enable register warn = command warning cal = calibration summary temp = temperature summary & = logical and or = logical or & & & 0 (b13 - b9) (b14) (b8) (b15) 0 warn cal questionable event register (b13 - b9) (b14) (b8) (b15) to questionable summary bit (qsb) of status byte register (see figure 4-10). (b7 - b5) (b7 - b5) (b7 - b5) warn cal 0 warn cal (b4) temp (b4) temp (b3 - b0) (b3 - b0) (b3 - b0) (b4) temp & remote operation 4-23 figure 4-8 measurement event status figure 4-9 questionable event status queues the model 2000 uses two queues, which are rst-in, ?st-out (fifo) registers: output queue - used to hold reading and response messages error queue - used to hold error and status messages the model 2000 multimeter status model (figure 4-5) shows how the two queues are struc- tured with the other registers. output queue the output queue holds data that pertains to the normal operation of the instrument. for ex- ample, when a query command is sent, the response message is placed on the output queue. when data is placed in the output queue, the message available (mav) bit in the status byte register sets. a data message is cleared from the output queue when it is read. the output queue is considered cleared when it is empty. an empty output queue clears the mav bit in the status byte register. read a message from the output queue by addressing the model 2000 multimeter to talk af- ter the appropriate query is sent. error queue the error queue holds error and status messages. when an error or status event occurs, a message that de nes the error/status is placed in the error queue. this queue will hold up to 10 messages. when a message is placed in the error queue, the error available (eav) bit in the status byte register is set. an error message is cleared from the error/status queue when it is read. the er- ror queue is considered cleared when it is empty. an empty error queue clears the eav bit in the status byte register. read an error message from the error queue by sending either of the following scpi query commands and then addressing the model 2000 to talk: :system:error? :status:queue see section 5 for complete information about reading error messages. 4-24 remote operation status byte and service request (srq) service request is controlled by two 8-bit registers: the status byte register and the service request enable register. figure 4-10 shows the structure of these registers. status summary messages * stb? serial poll osb (b7) rqs (b6) mss esb (b5) mav (b4) qsb (b3) eav (b2) (b1) (b0) or * sre * sre? status byte register service request enable register osb = operation summary bit mss = master summary status rqs = request for service esb = event summary bit mav = message available qsb = questionable summary bit eav = error available msb = measurement summary bit & = logical and or = logical or osb (b7) (b6) esb (b5) mav (b4) qsb (b3) eav (b2) (b1) (b0) & & & & & msb msb & service request generation read by serial poll read by *stb? remote operation 4-25 figure 4-10 status byte and service request (srq) status byte register the summary messages from the status registers and queues are used to set or clear the ap- propriate bits (b0, b2, b3, b4, b5, and b7) of the status byte register. these bits do not latch, and their states (0 or 1) are solely dependent on the summary messages (0 or 1). for example, if the standard event status register is read, its register will clear. as a result, its summary mes- sage will reset to 0, which in turn will clear the esb bit in the status byte register. bit b6 in the status byte register is either: the master summary status (mss) bit, sent in response to the *stb? command, indi- cates the status of any set bits with corresponding enable bits set. the request for service (rqs) bit, sent in response to a serial poll, indicates which de- vice was requesting service by pulling on the srq line. for a description of the other bits in the status byte register, see ?ommon commands, *stb? the ieee-488.2 standard uses the following common query command to read the status byte register: *stb?. when reading the status byte register using the *stb? command, bit b6 is called the mss bit. none of the bits in the status byte register are cleared when using the *stb? command to read it. the ieee-488.1 standard has a serial poll sequence that also reads the status byte register and is better suited to detect a service request (srq). when using the serial poll, bit b6 is called the rqs bit. serial polling causes bit b6 (rqs) to reset. serial polling is discussed in more detail later in this section entitled ?erial poll and srq.? any of the following operations clear all bits of the status byte register: cycling power. sending the *cls common command note: the mav bit may or may not be cleared. 4-26 remote operation service request enable register this register is programmed by you and serves as a mask for the status summary message bits (b0, b2, b3, b4, b5, and b7) of the status byte register. when masked, a set summary bit in the status byte register cannot set bit b6 (mss/rqs) of the status byte register. converse- ly, when unmasked, a set summary bit in the status byte register sets bit b6. a status summary message bit in the status byte register is masked when the corresponding bit in the service request enable register is cleared (0). when the masked summary bit in the status byte register sets, it is anded with the corresponding cleared bit in the service request enable register. the logic ??output of the and gate is applied to the input of the or gate and, thus, sets the mss/rqs bit in he status byte register. the individual bits of the service request enable register can be set or cleared by using the following common command: *sre serial poll and srq any enabled event summary bit that goes from 0 to 1 will set rqs and generate a service request (srq). in your test program, you can periodically read the status byte register to check if a service request (srq) has occurred and what caused it. if an srq occurs, the program can, for example, branch to an appropriate subroutine that will service the request. typically, service requests (srqs) are managed by the serial poll sequence of the model 2000. if an srq does not occur, bit b6 (rqs) of the status byte register will remain cleared and the program will simply proceed normally after the serial poll is performed. if an srq does occur, bit b6 of the status byte register will set and the program can branch to a service subroutine when the srq is de- tected by the serial poll. the serial poll automatically resets rqs of the status byte register. this allows subsequent serial polls to monitor bit b6 for an srq occurrence generated by other event types. after a se- rial poll, the same event can cause another srq, even if the event register that caused the rst srq has not been cleared. a serial poll clears rqs but does not clear mss. the mss bit stays set until all status byte event summary bits are cleared. the following quickbasic 4.5 program (using the kpc-488.2 interface and the cechp driver) demonstrates how serial poll can be used to detect an srq: cls open "ieee" for output as #1 open "ieee" for input as #2 print #1, "output 16; *cls" 'clear status byte register print #1, "output 16; *ese 32 'unmask command errors print #1, "output 16; *sre 32 'unmask event summary message print #1, "output 16; *ese" 'error - missing parameter sleep 1 print #1, "spoll 02" 'serial poll 2000 input #2, s 'read status byte register s=s or 191 'or register with a mask if s= 255 then gosub srq 'go to subroutine to acknowledge srq end if print end srq: print "srq has occurred--rqs (bit b6) is set (1)" return 4-28 remote operation trigger model (gpib operation) this section describes how the model 2000 multimeter operates over the gpib bus. the ?wchart in figure 4-11 summarizes operation over the bus and is called the trigger model. it is called the trigger model because operation is controlled by scpi commands from the trigger subsystem (see section 5 for more information). key scpi commands are included in the trigger model. :abort *rcl :syst:pres language change no yes idle and initiate :trigger:signal control source :trigger:source immediate :trigger:source external :trigger:source timer :trigger:source manual :trigger:source bus :trigger:delay idle and initiate the instrument is considered to be in the idle state whenever it is not operating. while in the idle state, the instrument cannot perform any measure or scan functions. you can send two com- mands over the bus to remove the instrument from the idle state: :initiate :initiate:continuous on with continuous initiation enabled (:initiate:continuous on), the instrument will not re- main in the idle state after all programmed operations are completed. however, you can return the instrument to the idle state at any time by sending any of these commands: *rst abort *rcl syst:pres trigger model operation once the instrument is taken out of idle, operation proceeds through the trigger model down to the device action. in general, the device action includes a measurement and, when scanning, closes the next channel. control source as shown in figure 4-11, a control source is used to hold up operation until the programmed event occurs. the control source options are explained as follows: immediate ?event detection is immediately satis ed allowing operation to continue. manual ?event detection is satis ed by pressing the trig key. the model 2000 mul- timeter must be in local mode for it to respond to the trig key. press the local key or send local 16 over the bus to remove the instrument from the remote mode. timer ?event detection is immediately satis ed on the initial pass through the loop each subsequent detection is satis ed when the programmed timer interval (0 to 999999.999) seconds elapses. the timer source is only available during step/scan oper- ation. the timer resets to its initial state when the instrument goes into the normal mode of operation or into the idle state. external ?event detection is satis ed when an input trigger via the trigger link connector is received by the model 2000 multimeter. bus ?event detection is satis ed when a bus trigger (get or *trg) is received by the model 2000 multimeter. delay a programmable delay is available after the event detection. the delay can be man- ually set from 0 to 999999.999 seconds, or auto delay can be used. with auto delay enabled, the instrument automatically selects a delay based on the selected function and range. see the auto delay table in section 3 for delay times. auto delay is typically used for scanning. the nominal delay will be just long enough to al- low each relay to settle before making the measurement. 4-30 remote operation device action figure 4-12 provides a detailed look at the device action. if the repeat lter is enabled, then the instrument samples the speci ed number of reading conversions to yield a single ?tered reading. if the moving ?ter is active, or ?ter is disabled, then only one reading conversion is performed. if the hold feature is enabled (see :hold commands in section 5), then the rst processed reading becomes the "seed" reading and operation loops back to the beginning of the device ac- tion. after the next reading is processed, it is compared to the programmed hold window (0.01% to 20%). if the reading is within the window, then operation again loops back to the beginning of the device action. this looping action continues until the speci ed number (2 to 100) of valid hold readings (readings within the window) have occurred. if one of the hold readings is not within the window, then the instrument acquires a new "seed" reading and repeats the hold pro- cess. after the hold is released, an audible beep is sounded to signal a valid measurement. the use of hold is explained in section 3. if the instrument is performing a step or scan, then the next task for device action is to open the previous channel (if closed) and close the next channel. if the ?ter, hold feature and scanning are disabled, the device action would simply be a single reading conversion. from delay block of trigger model (see figure 4-11) device action to output trigger block of trigger model (see figure 4-11). conv hold chan filtering process (filter enabled) conv = reading conversion hold = hold feature process (if enabled) chan = close channel (if scanning) conv conv remote operation 4-31 figure 4-12 device action (trigger model) programming syntax the information in this section covers syntax for both common commands and scpi com- mands. for information not covered here, see the ieee- 488.2 and scpi standards. command words program messages are made up of one or more command words. commands and command parameters common commands and scpi commands may or may not use a parameter. the following are some examples: *sav parameter types: the following are some of the more common parameter types: boolean: used to enable or disable an instrument operation. 0 or off dis- ables the operation, and 1 or on enables the operation. example: :current:ac:range:auto on enable auto ranging
query commands this type of command requests (queries) the currently programmed status. it is identi ed by the question mark (?) at the end of the fundamental form of the command. most commands have a query form, example: :trigger:timer? queries the timer interval. most command that require a numeric parameter( short-form rules use the following rules to determine the short-form version of any scpi command: if the length of the command word is four letters or less, no short form version exists. example: :auto = :auto these rules apply to command words that exceed four letters: if the fourth letter of the command word is a vowel, delete it and all the letters after it. example :immediate = :imm rule exception-the short form version of the following command uses only the rst two letters of the word: :tcouple = :tc if the fourth letter of the command word is a consonant, retain it but drop all the letters after it. example: :format = :form if the command contains a question mark (?; query) or a non- optional number included in the command word, you must include it in the short-form version. example: :delay? = :del? command words or characters that are enclosed in brackets ([ ]) are optional and need not be included in the program message. remote operation 4-35 program messages a program message is made up of one or more command words sent by the computer to the instrument. each common command is simply a three letter acronym preceded by an asterisk (*). scpi commands are categorized in the :status subsystem and are used to help explain how command words are structured to formulate program messages. :status path (root) :operation path :enable command path rules each new program message must begin with the root command, unless it is optional (e.g., [:sense]). if the root is optional, simply treat a command word on the next level as the root. the colon (:) at the beginning of a program message is optional and need not be used. example: :stat:pres = stat:pres when the path pointer detects a colon (:) it moves down to the next command level. an exception is when the path pointer detects a semicolon (;), which is used to separate com- mands within the program message (see next rule). when the path pointer detects a colon (:) that immediately follows a semicolon (;), it re- sets back to the root level. the path pointer can only move down. it cannot be moved up a level. executing a com- mand at a higher level requires that you start over at the root command. using common commands and scpi commands in the same message both common commands and scpi commands can be used in the same message as long as they are separated by semicolons (;). a common command can be executed at any command lev- el and will not affect the path pointer. example: :stat:oper:enab response messages a response message is the message sent by the instrument to the computer in response to a query command program message. sending a response message after sending a query command, the response message is placed in the output queue. when the model 2000 multimeter is then addressed to talk, the response message is sent from the out- put queue to the computer. multiple response messages if you send more than one query command in the same program message (see the paragraph entitled, ?ultiple command messages?, the multiple response messages for all the queries is sent to the computer when the model 2000 is addressed to talk. the responses are sent in the order that the query commands were sent and are separated by semicolons (;). items within the same query are separated by commas (,). the following example shows the response message for a program message that contains four single item query commands: 0; 1; 1; 0 response message terminator (rmt) each response is terminated with an lf (line feed) and eoi (end or identify). the following example shows how a multiple response message is terminated: 0; 1; 1; 0; common commands common commands (summarized in table 4-4) are device commands that are common to all devices on the bus. these commands are designated and de ned by the ieee-488.2 standard. table 4-4 ieee-488.2 common commands and queries mnemonic name description *cls *ese *cls clear status clear status registers and error queue description use the *cls command to clear (reset to 0) the bits of the following registers in the model 2000: standard event register operation even register error queue measurement event register questionable event register this command also forces the instrument into the operation complete command idle state and operation complete query idle state. *ese the standard event enable register is shown in figure 4-13 and includes the decimal weight of each bit. the sum of the decimal weights of the bits that you wish to be set is the parameter value that is sent with the *ese command. for example, to set the cme and qye bits of the standard event enable register, send the following command: *ese 36 where: cme (bit b5) = decimal 32 qye (bit b2) = decimal 4 *esr? event status register query read the standard event status register and clear it description use this command to acquire the value (in decimal) of the standard event register (see fig- ure 4-14). the binary equivalent of the returned decimal value determines which bits in the reg- ister are set. the register is cleared on power-up or when *cls is sent. a set bit in this register indicates that a particular event has occurred. for example, for an ac- quired decimal value of 48, the binary equivalent is 00110000. from this binary value, bits b4 and b5 of the standard event status register are set. these bits indicate that a device-dependent error and command error have occurred. the bits of the standard event status register are described as follows: bit b0, operation complete ?a set bit indicates that all pending selected device oper- ations are completed and the model 2000 is ready to accept new commands. this bit only sets in response to the *opc? query command. bit b1 ?not used bit b2, query error (qye) ?a set bit indicates that you attempted to read data from an empty output queue. bit b3, device-dependent error (dde) ?a set bit indicates that an instrument opera- tion did not execute properly due to some internal condition. bit b4, execution error (exe) ?a set bit indicates that the model 2000 detected an error while trying to execute a command. bit b5, command error (cme) ?a set bit indicates that a command error has occurred. command errors include: ieee-488.2 syntax error: model 2000 received a message that does not follow the de- ?ed syntax of the ieee-488.2 standard. semantic error: model 2000 received a command that was misspelled, or received an op- tional ieee-488.2 command that is not implemented. the instrument received a group execute trigger (get) inside a program message. bit b6, user request (urq) ?a set bit indicates that the local key on the model 2000 front panel was pressed. bit b7, power on (pon) ?a set bit indicates that the model 2000 has been turned off and turned back on since the last time this register has been read. 4-42 remote operation *idn? identi cation query read the identi cation code description the identi?ation code includes the manufacturer, model number, serial number, and ?m- ware revision levels, and is sent in the following format: keithley instruments inc., model 2000, xxxxxxx, yyyyy/zzzzz where: xxxxxxx is the serial number yyyyy/zzzzz is the rmware revision levels of the digital board rom and display board rom. b7 b6 b5 b4 b3 b2 b1 b0 0/1 0/1 0/1 bit position event decimal weighting value value : 1 = event bit set 0 = event bit cleared events : pon = power on urq = user request cme = command error exe = execution error dde = device-dependent error qye = query error opc = operation complete pon urq cme exe dde qye opc 0/1 0/1 0/1 0/1 (2 ) 7 (2 ) 6 (2 ) 5 (2 ) 4 (2 ) 3 (2 ) 2 (2 ) 0 64 32 1 128 16 8 4 note : bits b8 through b15 are not shown since they are not used. figure 4-14 standard event status regster remote operation 4-43 *opc operation complete set the opc bit in the standard event status register after all pending commands are complete description on power-up or when the *cls or *rst is executed, the model 2000 goes into the operation complete command idle state (ocis). in this state, no pending overlapped commands exist. the model 2000 has three overlapped commands: :initiate :initiate:continuous on *trg when you send the *opc command, the model 2000 exits from ocis and enters the oper- ation complete command active state (ocas). in ocas, the instrument continuously moni- tors the no-operation-pending ag. after the last pending overlapped command is completed (no-operation- pending ag set to true), the operation complete (opc) bit in the standard event status register sets, and the instrument goes back into ocis. note that the instrument always goes into ocas when *opc is executed. if no pending com- mand operations are present (e.g. trigger model in idle state), the model 2000 immediately sets the opc bit and returns to ocis. when used with the :initiate or :initiate:continuous on command, the opc bit of the standard event status register will not set until the model 2000 goes back into the idle state. the initiate operations are not considered nished until the instrument goes into idle. when used with the *trg command, the opc bit will not set until the operations associated with the *trg command (and the initiate command) are nished. the *trg command is con- sidered to be nished when the device action completes or when operation stops a control source to wait for an event (see trigger model in this section). to use the *opc exclusively with the *trg command, rst force the completion of the ini- tiate command so that only the *trg command is pending. do this by sending the :abort command to place the instrument in idle, which (by de nition) completes the initiate command. since continuous initiation is on, operation continues on into the trigger model. after sending the *trg command, the opc bit sets when the *trg command is nished. 4-44 remote operation program fragment gosub read register 'clear register by reading it print #1, "output 16; :init 'place 2000 in idle :cont off; :abort" print #1, "output 16; :init;*opc" 'start measurements and send *opc sleep 2 'wait two seconds gosub readregister 'read register to show that opc is not set print #1, "output 16; :abort" 'place 2000 back in idle gosub readregister 'read register to show that opc is now set end readregister: print #1, "output 16; *esr?" 'query standard event status reg- ister print #1, "enter 16" 'get response message from 2000 line input #2, a$ 'read decimal value of register print a$ return remote operation 4-45 *opc? operation complete query place a 1 in the output queue after all pending operations are completed description on power-up or when the *cls or *rst is executed, the model 2000 goes into the operation complete command query idle state (oqis). in this state, no pending overlapped commands exist. the model 2000 has three overlapped commands: :initiate :initiate:continuous on *trg when you send the *opc? command, the model 2000 exits from oqis and enters the oper- ation complete command query active state (oqas). in oqas, the instrument continuously monitors the no-operation-pending ag. after the last pending overlapped command is com- pleted (no- operation-pending ag set to true), an ascii character ??is placed into the output queue, the message available (mav) bit in the status byte sets, and the instrument goes back into oqis. addressing the model 2000 to talk sends the ascii ??to the computer. note that the instrument always goes into oqas when *opc? is executed. if no pending command operations are present (e.g. trigger model in idle state), the model 2000 immediately places an ascii ??in the output queue, sets the mav bit and returns to oqis. when used with the :initiate or :initiate:continuous on command, an ascii ??will not be sent to the output queue and the mav bit will not set until the model 2000 goes back into the idle state. the initiate operations are not considered nished until the instrument goes into the idle state. when used with the *trg command, an ascii ??will not be placed into the output queue and the mav bit will not set until the operations associated with the *trg command (and the initiate command) are nished. the *trg command is considered to be nished when the de- vice action completes or when operation stops at a control source to wait for an event (see the trigger model in this section). to use *opc? exclusively with the *trg command, rst force the completion of the initiate command so that only the *trg command is pending. to do this, send the :abort command to place the instrument in idle, which (by de nition) completes the initiate command. since con- tinuous initiation is on, operation continues on into the trigger model. after sending the *trg command, an ascii ??is placed in the output queue and the mav bit sets when the *trg command is nished. after *opc? is executed, additional commands cannot be sent to the model 2000 until the pending overlapped commands are nished. for example, :initiate:continuous on followed by *opc? locks up the instrument and requires a device clear (dcl or sdc) before it will ac- cept any more commands. note: see *opc, *trg and *wai for more information. 4-46 remote operation program fragment print #1, "output 16; :syst:pres" 'select defaults print #1, "output 16; :init:cont off;:abort" 'place 2000 in idle print #1, "output 16; :trig:coun 1; sour tim" print #1, "output 16; :samp:coun 5" 'program for 5 measurements and stop (idle) print #1, "output 16; :init; *opc?" 'start measurements and send *opc? print #1, "enter 16" 'get response when 2000 goes into idle line input #2, a$ 'read contents of output queue print a$ 'display the ascii "1" *opt? option identi cation query determine if an option is installed description the response message indicates the presence or absence of an optional scanner card. for ex- ample: 0 no scanner card installed 200x-scan scanner card installed *rcl recall return to setup stored in memory parameters *rst reset return 2000 to *rst defaults description when the *rst command is sent, the model 2000 performs the following operations: 1. returns the model 2000 to the *rst default conditions (see scpi tables). 2. cancels all pending commands. 3. cancels response to any previously received *opc and *opc? commands. *sav save save present setup in memory parameters sponding bit in the status byte register is set by an appropriate event. for more information on register structure, see the information presented earlier in this section. the service request enable register is shown in figure 4-15. notice that the decimal weight of each bit is included in the illustration. the sum of the decimal weights of the bits that you wish to set is the value that is sent with the *sre command. for example, to set the esb and mav bits of the service request enable register, send the following command: *sre 48 where: esb (bit b5) = decimal 32 mav(bit b4) = decimal 16 *stb? status byte query read status byte register description use the *stb? query command to acquire the value (in decimal) of the status byte register. the status byte register is shown in figure 4-16. the binary equivalent of the decimal value determines which bits in the register are set. all bits, except bit b6, in this register are set by other event registers and queues. bit 6 sets when one or more enabled conditions occur. the *stb? query command does not clear the status byte register. this register can only be cleared by clearing the related registers and queues. see ?tatus structure?for details. for example, for an acquired decimal value of 48, the binary equivalent is 00110000. this binary value indicates that bits 4 and 5 if the status byte register are set. the bits of the status byte register are described as follows: bit 0, measurement status (msb)-a set bit indicates that a measurement event has oc- curred. the event can be identi ed by reading the measurement event status register using the :status:measurement? command (see section 5 for details). bit 1-not used. bit 2, error available (eav)-a set bit indicates that an error or status message is present in the error queue. the message can be read using one of the following scpi com- mands: :system:error? :status:queue? see section 5 for more information. bit 3, questionable summary bit (qsb)-a set bit indicates that a calibration error has occurred. bit 4, message available (mav)-a set bit indicates that a message is present in the out- put queue. the message is sent to the computer when the model 2000 is addressed to talk. bit 5, event summary bit (esb)-a set bit indicates that an enabled standard event has occurred. the event can be identi ed by reading the standard event status register us- ing the *ese? query command. bit 6, master summary status (mss)/request service (rqs)-a set bit indicates that one or more enabled status byte conditions have occurred. read the mss bit by using the stb? query command, or perform a serial poll to detect the occurrence of a service re- quest (rqs bit set). bit 7, operation summary (osb)-a set bit indicates that an enabled operation event has occurred. the event can be identi ed by reading the operation event status register us- ing the :status:operation? query command (see section 5 for details). 4-50 remote operation *trg trigger send bus trigger to 2000 description use the *trg command to issue a gpib trigger to the model 2000. it has the same effect as a group execute trigger (get). use the *trg command as an event to control operation. the model 2000 reacts to this trig- ger if bus is the programmed control source. the control source is programmed from the trig- ger subsystem (see section 5). *tst?-self-test query run self test and read result description use this query command to perform a checksum test on rom. the command places the cod- ed result (0 or 1) in the output queue. when the model 2000 is addressed to talk, the coded re- sult is sent from the output queue to the computer. a returned value of zero (0) indicates that the test passed, and a value of one (1) indicates that the test has failed. b7 b6 b5 b4 b3 b2 b1 b0 (2 ) (2 ) 6 (2 ) 5 (2 ) 4 (2 ) 3 (2 ) 2 (2 ) 0 32 0/1 bit position event decimal weighting value value : 1 = event bit set 0 = event bit cleared events : osb = operation summary bit mss = master summary status rqs = request service esb = event summary bit mav = message available qsb = questionable summary bit eav = error available msb = measurement summary bit osb esb mav qsb eav 0/1 0/1 0/1 0/1 128 16 8 4 mss, rqs 64 0/1 msb 1 0/1 7 figure 4-16 status byte regis- ter remote operation 4-51 *wai wait-to-continue prevent execution of commands until previous commands are completed description two types of device commands exist: sequential commands-a command whose operations are allowed to ?ish before the next command is executed. overlapped commands-a command that allows the execution of subsequent commands while device operations of the overlapped command are still in progress. use the *wai command to suspend the execution of subsequent commands until the device operations of all previous overlapped commands are nished. the *wai command is not need- ed for sequential commands. the model 2000 has three overlapped commands: :initiate :initiate:continuous on *trg note: see *opc, *opc? and *trg for more information. the :initiate commands remove the model 2000 from the idle state. the device operations of :initiate are not considered complete until the model 2000 returns to idle. by sending the *wai command after the :initiate command, all subsequent commands will not execute until the model 2000 goes back into idle. the *trg command issues a bus trigger that could be used to provide the arm, scan, and measure events for the trigger model. by sending the *wai command after the *trg com- mand, subsequent commands will not executed until the pointer for the trigger model has n- ished moving in response to *trg and has settled at its next state. program fragment print #1, "output 02; :syst:pres" 'select defaults print #1, "output 02; :init:cont off;:abort" 'place 2000 in idle print #1, "output 02; :trig:coun 1;sour tim" 'program for 30 measurements and 'then stop (idle) print #1, "output 02; :samp:coun 30" print #1, "output 02;:init; *wai" 'start measurements and send *wai print #1, "output 02; :data?" 'query a reading print #1, "enter 02" 'get reading after 2000 goes into idle line input #2, a$ 'read the reading print a$ 'display the reading 4-52 remote operation 5 scpi command reference this section contains reference information on programming the model 2000 with the scpi commands. it is organized as follows: scpi signal oriented measurement commands covers the signal oriented measure- ment commands. these commands are used to acquire readings. scpi command subsystems reference tables includes a summary table for each scpi subsystem command. scpi command subsystems includes additional information on each scpi subsystem command. 5-2 scpi command reference scpi signal oriented measurement commands the signal oriented measurement commands are used to acquire readings. you can use these high-level instructions to control the measurement process. these commands are summarized in table 5-1. configure command :configure: the control source of the trigger model is set to immediate. the count values of the trigger model are set to one. the delay of the trigger model is set to zero. the model 2000 is placed in the idle state. all math calculations are disabled. buffer operation is disabled. a storage operation currently in process will be aborted. autozero is set to the *rst default value. all operations associated with switching cards (scanning) are disabled. this command is automatically asserted when the :measure? command is sent. program print #1, ?utput 16; :conf:volt:dc ?erform :configure opera- tions. fetch? command :fetch? description this query command requests the latest post- processed reading. after send- ing this command and addressing the model 2000 to talk, the reading is sent to the computer. this command does not affect the instrument setup. this command does not trigger a measurement. the command simply re- quests the last available reading. note that this command can repeatedly re- turn the same reading. until there is a new reading, this command continues to return the old reading. if your application requires a ?resh?reading, use the :data:fresh? command (see the sense subsystem command). this command is automatically asserted when the :read? or :measure? command is sent. note if external rapid triggers are applied, the unit may not return read- ings when using :fetch? 5-4 scpi command reference read? command :read? description typically, this command is used with the instrument in the ?ne-shot?mea- surement mode to trigger and acquire a speci ed number of readings. the :sample:count command is used to specify the number of readings (see trigger subsystem). note that the readings are stored in the buffer. when this command is sent, the following commands execute in the order that they are presented: :abort :initiate :fetch? when :abort is executed, if continuous initiation is disabled, the instru- ment goes into the idle state. if continuous initiation is enabled, the operation re-starts at the beginning of the trigger model. if the instrument is in the idle state, :initiate takes the instrument out of the idle state. if continuous initiation is enabled, (:initiate:continuous on), then the :initiate command generates an error and ignores the command. see the :fetch? command for more details. note that an ?nit ignored?er- ror will not cancel the execution of the :fetch? command. note you cannot use the :read? command if sample count >1 (see trigger subsystem) and there are readings stored in the buffer (er- ror -225, out of memory). either set sample count to one or clear the buffer. see appendix c for an example program using the read? com- mand. scpi command reference 5-5 measure command :measure[: scpi command subsystems reference tables tables 5-2 through 5-11 summarize the commands for each scpi subsystem. the following list includes the scpi subsystem commands and the table number where each command is summarized. calculate command summary (table 5-2) display command summary (table 5-3) format command summary (table 5-4) route command summary (table 5-5) sense command summary (table 5-6) status command summary (table 5-7) system command summary (table 5-8) trace command summary (table 5-9) trigger command summary (table 5-10) unit command summary (table 5-11) general notes: brackets ([ ]) are used to denote optional character sets. these optional characters do not have to be included in the program message. do not use brackets in the program message. angle brackets (< >) are used to indicate parameter type. do not use angle brackets in the program message. the boolean parameter () is used to enable or disable an instrument operation. 1 or on enables the operation and 0 or off disables the oper- ation. upper case characters indicate the short-form version for each command word. default parameter ?listed parameters are both the *rst and :sys- tem:preset defaults, unless noted otherwise. parameter notes are locat- ed at the end of each table. scpi ?a checkmark ( ) indicates that the command and its parameters are scpi con rmed. an unmarked command indicates that it is non-sc- pi. scpi con rmed commands that use one or more non-scpi parameters are explained by notes. scpi command reference 5-7 table 5-2 calculate command summary command description default parameter scpi :calculate[1] :format table 5-3 display command summary command description default parameter scpi :display [:window[1]] :text :data :data? :state :state? :enable :enable? path to control user text messages. de?e ascii message ??(up to 12 characters). query text message. enable or disable message mode. query text message state. enable or disable the front panel display. query state of the display. (note 1) (note 2) (note 3) notes: 1. *rst and :system:preset has no effect on a user de?ed message. cycling power cancels all user de?ed messages. 2. *rst and :system:preset has no effect on the state of the message mode. cycling power disables (off) the message mode. 3. *rst and :system:preset has no effect on the display circuitry. cycling power enables (on) the display circuitry. table 5-4 format command summary command description default parameter scpi :format [:data] |