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rev. 0 a information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 www.analog.com fax: 781/326-8703 ? analog devices, inc., 2002 three-phase energy meter chipset ADSST-EM-2030 * * protected by u.s.patent no. 5,969,657; other patents pending. microconverter is a registered trademark of analog devices. functional block diagram e-pulse ADSST-EM-2030 ?ontroller optical port op amp + mux counter lcd display rtc pt pt pt ct ct ct poly phase energy meter using the ADSST-EM-2030 features 3-phase, 4-wire metering ic high accuracy support for 50 hz/60 hz, iec1036 design accuracy: 0.5% over 5% of ib to 6% of ib 0.65% over 2% of ib to 5% of ib measures: kwh kw rms voltage of each phase rms current of each phase phase and nonlinearity compensation for cts potentiometer-free design spi communication for: data to microcontroller calibration programmable e-pulse drive for: electromechanical counter 2-phase stepper motor counter low power (50 mw typ) general description a dsst-em-2030 is a highly accurate and low cost phase en ergy measurement ic intended to be used in 3-phase, 4-wire systems. when used with an op amp and a multiplexer, the ADSST-EM-2030 surpasses the accuracy requirement of the iec1036 standard. ADSST-EM-2030 is a microconverter consisting of a microcon- troller, 6-channel, 12-bit adc, spi port, program memory and flash for storage of constants. the only analog circuitry used in ADSST-EM-2030 is the adc. all other signal processing is carried out in digital domain. this provides superior accuracy over extreme environmental conditions and time. ADSST-EM-2030 can drive an electromechanical counter or a 2-phase stepper motor counter, or can be interfaced to a mi crocontroller to build a feature-rich meter with lcd, maximum demand, time of use, and communication. ratio, phase, and nonlinearity errors of the cts are compensated for by using software. this reduces the cost of cts and reduces calibration time caused by unreliable potentiometers. because the ADSST-EM-2030 is a low power device, it can be powered by a simple r-c power supply, reducing the cost of operation. ADSST-EM-2030 supplies average real power information on the low frequency outputs f1 and f2. these logic outputs can be used to drive an electromechanical counter. the cf logic pin gives the instantaneous real power information. this output is intended to be used for calibration. ADSST-EM-2030 is available in a 28-lead ssop package.
rev. 0 e2e ADSST-EM-2030 pin function description pin no. mnemonic description 1 dgnd digital ground 2d load used to enable serial download of program memory 3g ain 1 logic channels output for multiplexer to switch gain for a-phase current 4g ain 2 logic channels output for multiplexer to switch gain for b-phase current 5 tamp logic output indicating that one more current is reversed 6c fc alibration frequency logic output. this gives instantaneous real power information and can be used for calibration. 7g ain 3 logic channels output for multiplexer to switch gain for c-phase current 8, 9 f1, f2 low frequency logic outputs. f1 and f2 provide average real power information. the logic outputs can be used to drive electromechanical counters and 2-phase stepper motors. 10 reset system reset 11 aphv a-phase voltage input 12 aphc a-phase current input 13 avdd analog positive supply 14 agnd analog ground 15 agnd analog ground 16 vref input for external voltage reference pin configuration dload gain 1 gain 2 ta m p cf gain 3 ss s s s s s ss s s ss ss sss s s s ss s s s ss s
rev. 0 ADSST-EM-2030 e3e serial peripheral interface (spi) the spi bus available on the ADSST-EM-2030 is useful to communicate to an external microcontroller as shown in figure 1. slave ADSST-EM-2030 master microcontroller figure 1. spi communication between ADSST-EM-2030 and microcontroller here, the microcontroller functions as master and the adsst- em-2030 is a slave for this protocol. using this communication port, the microcontroller will be able to read and write to the ADSST-EM-2030 to perform the following functions: calibrate the meter configure the ADSST-EM-2030 chipset read measured parameters from the ADSST-EM-2030 chipset four pins are used on the ADSST-EM-2030 chipset for the communication, and are shown table i. table i. pin description for spi communication port pin no. mnemonic description 22 ss s s s s s ss ss s ss ss s ss s s s s ss ss s ss ss s s s s s s s s s s s s s s ss ss s
rev. 0 ? ADSST-EM-2030 sclk ss miso mosi msb msb bits 6? bits6? lsb lsb t ss t df t sh t dav t dsu t dhd t sc t df t dr t sfs t sr t sf figure 2. spi communication port timing sclock ss sample input data output spi interrupt for 8712s msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 lsb ? figure 3. spi timing for data transmission byte spi functions three specific functions can be performed on the spi commu- nication port on the ADSST-EM-2030 chipset: data read?he external microcontroller can read the data from the ADSST-EM-2030 by sending specific commands; this includes m etering data, constants, and so on. data write?he external microcontroller can send data to the ADSST-EM-2030 to be stored in its internal nonvolatile memory; this includes calibration and configuration constants, and so on. special commands?he external microcontroller can send special commands to the ADSST-EM-2030 for performing specific functions. these commands do not have any data. data read the microcontroller being the master for the spi communication, has to send the desired commands for getting data from adsst- em-2030. for the data transfer to take place, the following sequence of operations must take place: 1. the microcontroller should send the specific command to the ADSST-EM-2030 chipset to read the desired data. 2. the ADSST-EM-2030 will first respond with an acknowl- edgment to the microcontroller within 5 ms that it has received the command. to send the acknowledgment, the ADSST-EM-2030 adds 0x30 to the received command, and which is then sent back to the microcontroller.
rev. 0 ADSST-EM-2030 e5e 3. if the microcontroller does not get this acknowledgment from the ADSST-EM-2030 within 5 ms then the microcon troller may transmit this command to read the same data again. 4. after being sensed by the microcontroller, the adsst-em- 2030 sends an acknowledgment to the microcontroller, the chipset then prepares a packet of 10 bytes of requested data and starts transmitting the bytes one by one at intervals of 5 ms. this packet of 10 bytes also includes a header as the first byte of the packet and checksum as the last byte. 5. the microcontroller can strip the data from this packet, compute the checksum, and compare it with the last byte in the packet. if the checksum does not match, the microcontroller should then send the command again to ADSST-EM-2030 chipset. the complete process of reading a packet of data should take 60 m s. the next command from the microcontroller to the ADSST-EM-2030 can be sent immediately after receipt of data or wait for the desired amount of time. the amount of time the microcontroller should wait for the next command to be sent to the ADSST-EM-2030 is purely dependent on the execution of other functions on the microcontroller. it may be sufficient fo r the microcontroller to collect data from the chipset after every sec ond. the remaining time may be used by the micro- controller to perform other housekeeping functions. for example, if the command sent by the microcontroller is 0x01, the ADSST-EM-2030 adds 0x30 to it, making it 0x31, and sends this to the microcontroller as an acknowledgment. the data packet structure created by the ADSST-EM-2030 has 10 bytes. the first byte is a packet start byte (0xee) and the last byte is a checksum byte. < start of packet (0xee) >< 8 bytes of data > < checksum > the checksum is calculated by adding the first nine bytes, includ- ing the packet start byte. checksum = 1 st + 2 nd + ...... ...... + 9 th b yte table iii shows various commands that can be sent to the adsst- em-2030 chipset by the microcontroller on the spi communication port. the chipset returns a specific number of bytes for each data parameter specified, in the data column of the table. the data that can be read from the chipset could be calibration constants or instantaneous data. table iii. read commands to ADSST-EM-2030 on spi command to number of data bytes function ADSST-EM-2030 from c from ADSST-EM-2030 constants gain calibration constants read voltage gain constants 0x01 6 read low gain current constants 0x02 6 read high gain current constants 0x03 6 power calibration constants at high current range a-phase power constant at high current (including e-pulse and counter pulse constant) 0x07 4 b-phase power constant at high current 0x09 2 c-phase power constant at high current 0x0b 2 power calibration constants at low current range a-phase power constant at low current 0x06 2 b-phase power constant at low current 0x08 2 c-phase power constant at low current 0x0a 2 phase compensation coefficients read a-, b-, and c-phase coefficients 0x15 6 dc offset constants read dc offset constants 0x0e 6 instantaneous parameters read voltages for phase a, b, and c 0x0f 6 read currents for phase a, b, and c 0x10 6 read energy and power for phase a, b, and c 0x11 8
rev. 0 e6e ADSST-EM-2030 data structure in the packet the ADSST-EM-2030 sends out eight bytes of data for every command. the last bytes of a parameter with a 6-byte structure are kept at zero and should be neglected. table iv. byte wise packet data structure for voltage gain constants command to ADSST-EM-2030: 0x01 acknowledgment from ADSST-EM-2030: 0x31 byte no. name description 1 spb start packet byte (0xee) 2 avms voltage constant for a-phase e msb 3 avls voltage constant for a-phase e lsb 4 bvms voltage constant for b-phase e msb 5 bvls voltage constant for b-phase e lsb 6 cvms voltage constant for c-phase e msb 7 cvls voltage constant for c-phase e lsb 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table v. byte wise packet data structure for low gain current constants command to ADSST-EM-2030: 0x02 acknowledgment from ADSST-EM-2030: 0x32 byte no. name description 1 spb start packet byte (0xee) 2 ailm current constant for a-phase e low gain e msb 3 aill current constant for a-phase e low gain e lsb 4 bilm current constant for b-phase e low gain e msb 5 bill current constant for b-phase e low gain e lsb 6 cilm current constant for c-phase e low gain e msb 7 cill current constant for c-phase e low gain e lsb 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table vi. byte wise packet data structure for high gain current constants command to ADSST-EM-2030: 0x03 acknowledgment from ADSST-EM-2030: 0x33 byte no. name description 1 spb start packet byte (0xee) 2 aihm current constant for a-phase e high gain e msb 3 aihl current constant for a-phase e high gain e lsb 4 bihm current constant for b-phase e high gain e msb 5 bihl current constant for b-phase e high gain e lsb 6 cihm current constant for c-phase e high gain e msb 7 cihl current constant for c-phase e high gain e lsb 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum 123456789 0 1 b p ss m v as l v as m v bs l v bs m v cs l v cv l nv l nm u s c 123456789 0 1 b p sm l i al l i am l i bl l i bm l i cl l i cv l nv l nm u s c 123456789 0 1 b p sm h i al h i am h i bl h i bm h i cl h i cv l nv l nm u s c
rev. 0 ADSST-EM-2030 e7e table vii. byte wise packet data structure for power constants at high current for phase a command to ADSST-EM-2030: 0x07 acknowledgment from ADSST-EM-2030: 0x37 byte no. name description 1 spb start packet byte (0xee) 2 pahm power constant for a-phase, high current e msb 3 pahl power constant for a-phase, high current e lsb 4 epc e-pulse constant in pulses per kwh (1 = 1600, 2 = 800, 3 = 400, and 4 = 200), default value = 1 5 cpc counter pulse constant in pulses per kwh (1 = 200 and 2 = 400), default value = 1 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table viii. byte wise packet data structure for power constants at high current for phase b command to ADSST-EM-2030: 0x09 acknowledgment from ADSST-EM-2030: 0x39 byte no. name description 1 spb start packet byte (0xee) 2 pbhm power constant for b-phase, high current e msb 3 pbhl power constant for b-phase, high current e lsb 4 nlv no legal value (0x00) 5 nlv no legal value (0x00) 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table ix. byte wise packet data structure for power constants at high current for phase c command to ADSST-EM-2030: 0x0b acknowledgment from ADSST-EM-2030: 0x3b byte no. name description 1 spb start packet byte (0xee) 2 pchm power constant for c-phase, high current e msb 3 pchl power constant for c-phase, high current e lsb 4 nlv no legal value (0x00) 5 nlv no legal value (0x00) 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum 123456789 0 1 b p sm h a pl h a pc p ec p cv l nv l nv l nv l nm u s c 123456789 0 1 b p sm h b pl h b pv l nv l nv l nv l nv l nv l nm u s c 123456789 0 1 b p sm h c pl h c pv l nv l nv l nv l nv l nv l nm u s c
rev. 0 e8e ADSST-EM-2030 table x. byte wise packet data structure for power constants at low current for phase a command to ADSST-EM-2030: 0x06 acknowledgment from ADSST-EM-2030: 0x36 byte no. name description 1 spb start packet byte (0xee) 2 palm power constant for a-phase, low current e msb 3 pall power constant for a-phase, low current e lsb 4 nlv no legal value (0x00) 5 nlv no legal value (0x00) 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table xi. byte wise packet data structure for power constants at low current for phase b command to ADSST-EM-2030: 0x08 acknowledgment from ADSST-EM-2030: 0x38 byte no. name description 1 spb start packet byte (0xee) 2 pblm power constant for b-phase, low current e msb 3 pbll power constant for b-phase, low current e lsb 4 nlv no legal value (0x00) 5 nlv no legal value (0x00) 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table xii. byte wise packet data structure for power constants at low current for phase c command to ADSST-EM-2030: 0x0a acknowledgment from ADSST-EM-2030: 0x3a byte no. name description 1 spb start packet byte (0xee) 2 pclm power constant for c-phase, low current e msb 3 pcll power constant for c-phase, low current e lsb 4 nlv no legal value (0x00) 5 nlv no legal value (0x00) 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum 123456789 0 1 b p sm l a pl l a pv l nv l nv l nv l nv l nv l nm u s c 123456789 0 1 b p sm l b pl l b pv l nv l nv l nv l nv l nv l nm u s c 123456789 0 1 b p sm l c pl l c pv l nv l nv l nv l nv l nv l nm u s c
rev. 0 ADSST-EM-2030 e9e table xiii. byte wise packet data structure for phase compensation coefficients command to ADSST-EM-2030: 0x15 acknowledgment from ADSST-EM-2030: 0x45 byte no. name description 1 spb start packet byte (0xee) 2 pga phase constant for low current e phase a 3 psa phase constant for high current e phase a 4 pgb phase constant for low current e phase b 5 psb phase constant for high current e phase b 6 pgc phase constant for low current e phase c 7 psc phase constant for high current e phase c 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table xiv. byte wise packet data structure for dc offset constants command to ADSST-EM-2030: 0x0e acknowledgment from ADSST-EM-2030: 0x3e byte no. name description 1 spb start packet byte (0xee) 2 dam dc offset for phase a - msb 3 dal dc offset for phase a e lsb 4 dbm dc offset for phase b e msb 5 dbl dc offset for phase b e lsb 6 dcm dc offset for phase c e msb 7 dcl dc offset for phase c e lsb 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table xv. byte wise packet data structure while reading instantaneous voltages in volts command to ADSST-EM-2030: 0x0f acknowledgment from ADSST-EM-2030: 0x3f voltage value resolution: two decimal points byte no. name description 1 spb start packet byte (0xee) 2 vam voltage for phase a e msb 3 val voltage for phase a e lsb 4 vbm voltage for phase b e msb 5 vbl voltage for phase b e lsb 6 vcm voltage for phase c e msb 7 vcl voltage for phase c e lsb 8 tamper info 0 bit: a e ct reversal first bit: b e ct reversal second bit: c e ct reversal third bit: phase sequence error 9 not used 10 csum checksum 123456789 0 1 b p sa g pa s pb g pb s pc g pc s pv l nv l nm u s c 123456789 0 1 b p sm a dl a dm b dl b dm c dl c dv l nv l nm u s c 1234567 89 0 1 b p sm a vl a vm b vl b vm c vl c v r e p m a t o f n i t o n d e s u m u s c
rev. 0 e10e ADSST-EM-2030 table xvi. byte wise packet data structure while reading instantaneous current in amperes command to ADSST-EM-2030: 0x10 acknowledgment from ADSST-EM-2030: 0x40 current value resolution: three decimal points byte no. name description 1 spb start packet byte (0xee) 2 iam current for phase a e msb 3 ial current for phase a e lsb 4 ibm current for phase b e msb 5 ibl current for phase b e lsb 6 icm current for phase c e msb 7 icl current for phase c e lsb 8 actr freq (msb) 9 actr freq (lsb) 10 csum checksum table xvii. byte wise packet data structure while reading instantaneous power and energy command to ADSST-EM-2030: 0x11 acknowledgment from ADSST-EM-2030: 0x41 power value (in kw) resolution: five decimal points energy value (in kwh) resolution: four decimal points byte no. name description 1 spb start packet byte (0xee) 2 pt1 total power first byte e msb 3 pt2 total power second byte 4 pt3 total power third byte 5 pt4 total power fourth byte e lsb 6 et1 total energy first byte e msb 7 et2 total energy second byte 8 et3 total energy third byte 9 et4 total energy fourth byte e lsb 10 csum checksum 123456789 0 1 b p sm a il a im b il b im c il c ir t c ar t c am u s c 123456789 0 1 b p s1 t p2 t p3 t p4 t p1 t e2 t e3 t e4 t em u s c
rev. 0 ADSST-EM-2030 e11e data interpretation the data sent by ADSST-EM-2030 is in hex, and the microcontroller has to convert this and place the decimal point at the correc t place for display. table xviii. interpretation of the voltage data the data sent for voltage has a resolution up to two decimal places. each phase voltage data hex value (2 byte) decimal value voltage 5a10h 23056 230.56 v table xix. interpretation of the current data the data sent for current has a resolution up to three decimal places. each phase current data hex value (2 byte) decimal value current 278bh 10123 10.123 a table xx. interpretation of the power data the data sent for power has a resolution up to five decimal places. each phase power data hex value (4 byte) decimal value power 0d1c4ah 859210 8.59210 kw table xxi. interpretation of the energy data the data sent for energy has a resolution up to four decimal places. each phase energy data hex value (4 byte) decimal value energy 0d1c4ah 859210 85.9210 kwh data write because microcontroller is the master for the spi communication, it has to send the desired commands for sending the data to the ADSST-EM-2030. for the data transfer to take place, the following sequence of operation has to occur: 1. the microcontroller should send the packet of 10 bytes including the specific command to the ADSST-EM-2030 chipset to write the desired data. thus, the packet of 10 bytes includes a header as the first byte of the packet, a specific command for write data, and checksum as the last byte. 2. the ADSST-EM-2030 will receive the bytes one by one in intervals of 5 ms. 3. the ADSST-EM-2030 strips the data from this packet, computes the checksum and compares it with the last byte in the packet. if the checksum does not match, the microcontroller should send the command to the ADSST-EM-2030 chipset again, else the ADSST-EM-2030 sends the acknowledgment of receipt of all the bytes to be written. 4. to send the acknowledgment, the ADSST-EM-2030 adds 0x30 to the received command, which is then sent back to the microcontroller. 5. if the microcontroller does not get this acknowledgment from the ADSST-EM-2030 by 5 ms, then the microcontroller may transmit this command to write the same data again. the complete process of writing a packet of data should take 60 ms. the next command from the microcontroller to the adsst -em- 2030 can be sent immediately after receipt of data or wait for the desired amount of time. the amount of time the microcon troller waits for the next command to be sent to ADSST-EM-2030 is purely dependent on the execution of other functions on the microcontroller. it may be sufficient for the microcontroller to collect data from the chipset after every one second. the re maining time may be used by the microcontroller to perform other housekeeping functions. for example, if the command sent by the microcontroller is 0x01; the ADSST-EM-2030 adds 0x30 to it, making it 0x31, and sends this to the microcontroller as an acknowledgment. the data packet structure created by the ADSST-EM-2030 has 10 bytes. the first byte is a packet start byte (0xee), and the last byte is a checksum byte. < start of packet (0xee) >< command of 1 byte > < 7 bytes of data >< checksum > the checksum is calculated by adding the first nine bytes in cluding the packet start byte. checksum = 1 st + 2 nd + ...... ...... + 9 th b yte
rev. 0 e12e ADSST-EM-2030 table xxii shows various commands that can be sent to the ADSST-EM-2030 chipset by the microcontroller on the spi communi- cation port. the chipset writes the specific number of bytes for each data parameter specified in the data column of the table. the data that can be written to the chipset could be calibration constants. table xxii. interpretation of the energy data command to data ADSST-EM-2030 data bytes gain calibration voltage coefficient 0x81 6 current low gain coefficient 0x82 6 current high gain coefficient 0x83 6 power calibration constants at high current range a-phase power constant at high current (with e-pulse and counter pulse) 0x87 4 b-phase power constant at high current 0x89 2 c-phase power constant at high current 0x8b 2 power calibration constants at low current range a-phase power constant at low current 0x86 2 b-phase power constant at low current 0x88 2 c-phase power constant at low current 0x8a 2 phase compensation coefficients a-, b-, c-phase coefficient 0x95 6 data structure in the packet the ADSST-EM-2030 sends out seven bytes of data for every command. the last bytes of a 6-byte structure are kept at zero and should be neglected. table xxiii. byte wise packet data structure for voltage gain constants command to ADSST-EM-2030: 0x81 acknowledgment from ADSST-EM-2030: 0xb1 byte no. name description 1 spb start packet byte (0xee) 2 cwv command to write voltage constant 3 wavm voltage constant for a-phase e msb 4 wavl voltage constant for a-phase e lsb 5 wbvm voltage constant for b-phase e msb 6 wbvl voltage constant for b-phase e lsb 7 wcvm voltage constant for c-phase e msb 8 wcvl voltage constant for c-phase e lsb 9 nlv no legal value (0x00) 10 csum checksum 12 3 4 5 6 7890 1 b p sv w cm v a wl v a wm v b wl v b wm v c wl v c wv l nm u s c
rev. 0 ADSST-EM-2030 e13e table xxiv. byte wise packet data structure for low gain current constants command to ADSST-EM-2030: 0x82 acknowledgment from ADSST-EM-2030: 0xb2 byte no. name description 1 spb start packet byte (0xee) 2 cwi command to write low gain current constant 3 waim current constant for a-phase e low gain e msb 4 wail current constant for a-phase e low gain e lsb 5 wbim current constant for b-phase e low gain e msb 6 wbil current constant for b-phase e low gain e lsb 7 wcim current constant for c-phase e low gain e msb 8 wcil current constant for c-phase e low gain e lsb 9 nlv no legal value (0x00) 10 csum checksum table xxv. byte wise packet data structure for high gain current constants command to ADSST-EM-2030: 0x83 acknowledgment from ADSST-EM-2030: 0xb3 byte no. name description 1 spb start packet byte (0xee) 2 cwhi command to write high gain current constant 3 wahim current constant for a-phase e high gain e msb 4 wahil current constant for a-phase e high gain e lsb 5 wbhim current constant for b-phase e high gain e msb 6 wbhil current constant for a-phase e high gain e lsb 7 wchim current constant for a-phase e high gain e msb 8 wchil current constant for a-phase e high gain e lsb 9 nlv no legal value (0x00) 10 csum checksum table xxvi. byte wise packet data structure for power constants at high current for phase a command to ADSST-EM-2030: 0x87 acknowledgment from ADSST-EM-2030: 0xb7 byte no. name description 1 spb start packet byte (0xee) 2 cwaph command to write power constant for a-phase at high current 3 wpahm power constant for a-phase, high current e msb 4 wpahl power constant for a-phase, high current e lsb 5 epc e-pulse constant in pulses per kwh (1 = 1600, 2 = 800, 3= 400, and 4 = 200), default value = 1 6 cpc counter pulse constant in pulses per kwh (1 = 200 and 2= 400), default value = 1 7 nlv no legal value (0x00) 8 nlv no legal lalue (0x00) 9 nlv no legal value (0x00) 10 csum checksum 12 3 4 5 6 7890 1 b p si w cm i a wl i a wm i b wl i b wm i c wl i c wv l nm u s c 12 3 4 5 6 7890 1 b p si h w cm i h a wl i h a wm i h b wl i h b wm i h c wl i h c wv l nm u s c 12 3 4 5 6789 0 1 b p sh p a w cn h a p wl h a p wc p ec p cv l nv l nv l nm u s c
rev. 0 e14e ADSST-EM-2030 table xxvii. byte wise packet data structure for power constants at high current for phase b command to ADSST-EM-2030: 0x89 acknowledgment from ADSST-EM-2030: 0xb9 byte no. name description 1 spb start packet byte (0xee) 2 cwbph command to write power constant for b-phase at high current 3 wpbhm power constant for b-phase, high current e msb 4 wpbhl power constant for b-phase, high current e lsb 5 epc no legal value (0x00) 6 cpc no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table xxviii. byte wise packet data structure for power constants at high current phase c command to ADSST-EM-2030: 0x8b acknowledgment from ADSST-EM-2030: 0xbb byte no. name description 1 spb start packet byte (0xee) 2c wcph command to write power constant for c phase at high current 3 wpchm power constant for c-phase, high current e msb 4 wpchl power constant for c-phase, high current e lsb 5 epc no legal value (0x00) 6 cpc no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table xxix. byte wise packet data structure for power constants at low current for phase a command to ADSST-EM-2030: 0x86 acknowledgment from ADSST-EM-2030: 0xb6 byte no. name description 1 spb start packet byte (0xee) 2 cwapl command to write power constant for a-phase at low current 3 wpalm power constant for a-phase, low current e msb 4 wpall power constant for a-phase, low current e lsb 5 nlv no legal value (0x00) 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum 12 3 45 6789 0 1 b p sh p b w cm h b p wl h b p wc p ec p cv l nv l nv l nm u s c 12 3 4 567890 1 b p sh p c w cm h c p wl h c p wc p ec p cv l nv l nv l nm u s c 12 3 456 789 0 1 b p sl p a w cm l a p wl l a p wv l nv l nv l nv l nv l nm u s c
rev. 0 ADSST-EM-2030 e15e table xxx. byte wise packet data structure for power constants at low current for phase b command to ADSST-EM-2030: 0x88 acknowledgment from ADSST-EM-2030: 0xb8 byte no. name description 1 spb start packet byte (0xee) 2 cwbpl command to write power constant for b-phase at low current 3 wpblm power constant for b-phase, low current e msb 4 wpbll power constant for b-phase, low current e lsb 5 nlv no legal value (0x00) 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table xxxi. byte wise packet data structure for power constants at low current for phase c command to ADSST-EM-2030: 0x8a acknowledgment from ADSST-EM-2030: 0xba byte no. name description 1 spb start packet byte (0xee) 2 cwcpl command to write power constant for c-phase at low current 3 wpclm power constant for c-phase, low current e msb 4 wpcll power constant for c-phase, low current e lsb 5 nlv no legal value (0x00) 6 nlv no legal value (0x00) 7 nlv no legal value (0x00) 8 nlv no legal value (0x00) 9 nlv no legal value (0x00) 10 csum checksum table xxxii. byte wise packet data structure for phase compensation coefficients command to ADSST-EM-2030: 0x95 acknowledgment from ADSST-EM-2030: 0xc5 byte no. name description 1 spb start packet byte (0xee) 2 cwpc command to write phase compensation coefficients 3 wpga phase constant for low current e phase a 4 wpsa phase constant for high current e phase a 5 wpgb phase constant for low current e phase b 6 wpsb phase constant for high current e phase b 7 wpgc phase constant for low current e phase c 8 wpsc phase constant for high current e phase c 9 nlv no legal value (0x00) 10 csum checksum 12 3 4 5 6789 0 1 b p sl p b w cm l b p wl l b p wv l nv l nv l nv l nv l nm u s c 12 3 4 567890 10 1 0 1 0 10 1 b p sl p c w cm l c p wl l c p wv l nv l nv l nv l nv l nm u s cm u s c m u s c m u s cm u s c 12 3 4 56789 0 1 b p sc p w ca g p wa s p wb g p wb s p wc g p wc s p wv l nm u s c
rev. 0 e16e ADSST-EM-2030 reset calibration to calibrate the meter using the ADSST-EM-2030, first reset the calibration. by sending a command 0x18 on the spi to the ADSST-EM-2030, the chipset automatically resets the calibration. procedure 1. power up the meter with standard voltage without any current on the current channels. 2. send 0x18 on the spi. dc offset calibration for voltage and current the dc offset calibration takes care of the dc offset that may be there in the signal path introduced by any of the front-end elements. by sending 0x0d command on the spi communication port to the ADSST-EM-2030, the chipset performs calculation of dc offsets on the voltage and current channels and stores the coefficients in its flash memory. while the calibration is in progress, communi- cation on spi will not be accepted by the chipset. procedure 1. power up the meter with standard voltage of all phases without any current on the current channels. 2. send 0x0d on the spi to perform dc offset calibration. 3. read back the coefficients on spi by sending 0x0e to the chipset. voltage gain calibration the ADSST-EM-2030 enables software calibration of the voltage channels to take care of tolerances for the passive components used in the signal path. procedure 1. power up the meter by setting the voltage source at 230 v on all the three phases (say v r ). 2. send 0x01 command on the spi to the chipset for reading the voltage constants as c va , c vb , and c vc. 3. the ADSST-EM-2030 will return back six bytes of voltage values for the three phases (v a , v b , and v c ). 4. compute the new constants on a pc or a calculator in hex as: = c v v c va r a va = c v v c vb r b vb = c v v c vc r c vc 5. these coefficients can then be written by sending the 0x81 command to the chipset on the spi. refer to table xxiii for the write data sequence. the coefficients are sent in the same sequence as in the table xxiii. this automatically stores the voltage constants in the chipset?s internal nonvolatile memory. 6. to verify the coefficients, send 0x01 to the chipset to receive the six bytes of data as voltage coefficients. 7. the default constants in the chipset for all the voltage channels is 0x709c. current calibration the ADSST-EM-2030 enables software calibration of the current channels to take care of tolerances for the passive components used in the signal path. low gain current calibration 1. power up the meter by setting the current source at 60 amps on all three phases (i r ). 2. send 0x02 command on the spi to the chipset for reading the current constants as: c ia , c ib , and c ic . special data the microcontroller sends some special commands to ADSST-EM-2030 for the special functions like dc offset calculation, initiali zing the energies, and resetting the calibration constants. the packet sent by the microcontroller to the ADSST-EM-2030 contains only th e command byte and no data bytes. on receiving the packet of command, the ADSST-EM-2030 sends back the acknowledgment to the micro- controller by adding 0x30 to the command value. if the microcontroller does not get this acknowledgment from the ADSST-EM-2030 by 5 ms, then the microcontroller may transmit this command to write the same data again. table xxxiii shows special commands that can be sent to the ADSST-EM-2030 chipset by the microcontroller on the spi commu- nication port. the chipset sends back the acknowledgment for each command to the microcontroller. the functions that are done b y the chipset are dc offset calibration, initialization of energies, and resetting the calibration constants. table xxxiii. special commands to the ADSST-EM-2030 on spi command to acknowledgment to function ADSST-EM-2030 the microcontroller comment dc offset calculates dc calculate dc offset 0x0d 0x3d offset constants initialization initializes the energy initialize 0x16 0x46 energy values to zero reset reset the calibration constants to the reset calibration 0x18 0x48 default values
rev. 0 ADSST-EM-2030 e17e 3. the ADSST-EM-2030 will return back six bytes of current values for the three phases: i a , i b , and i c . 4. compute the new constants on a pc or a calculator in hex as: 5. these coefficients can then be written by sending the 0x82 command to the chipset on the spi. refer to table xxiv for the write data sequence. the coefficients are sent in the same sequence as in the table xxiv. this automatically stores the current constants in the chipsets? internal nonvolatile memory. 6. to verify the coefficients, send 0x02 to the chipset to receive the six bytes of data as current coefficients. 7. the default constants in the chipset for all the low gain current channels is 0x7000. high gain current calibration 1. power up the meter by setting the current source at 5 amps on all three phases (i r ). 2. send 0x03 command on the spi to the chipset for reading the current constants as: c ia , c ib , and c ic . 3. the ADSST-EM-2030 will return back six bytes of current values for the three phases (i a , i b , i c ). 4. compute the new constants on a pc or a calculator in hex as: 5. these coefficients can then be written by sending the 0x83 command to the chipset on the spi. refer to table xxv for the write data sequence. the coefficients are sent in the same sequence as in table xxv. this automatically stores the current constants in the chipset?s internal nonvolatile memory. 6. to verify the coefficients, send 0x03 to the chipset to receive the six bytes of data as current coefficients. 7. the default constants in the chipset for all the high gain current channels is 0x2300. power calibration the meter can now be calibrated for power for each phase. the calculation requires the default constants that are stored in the internal nonvolatile memory. due to the chipset?s in-built feature of performing automatic gain switching for the current channels, the power needs to be calibrated at low gain (i.e., high currents) and high gain (i.e., low currents). it is recommended that low gain calibration is performed at i max and high gain calibration is performed at i nominal /2. in the present example, the meter is specified for 230 v operation with i max at 60 amps. low gain power calibration the default power constant for all three phases at low gain is 0x3ee4. by sending commands such as 0x07, 0x09, and 0x0b on the spi, the chipset will send six bytes each, corresponding to phases a, b, and c. procedure 1. power up the meter after setting the voltage at 230 v, cur rent at 60 amps and power factor at unity. 2. read the default power constants for phase a by sending 0x07 command on the spi. the chipset will return six bytes, giving the default constants p ca for power constants for phase a. 3. read the default constants for phase b by sending 0x09 command on the spi. the chipset will return six bytes, giving the default constants p cb for power constants for phase b. 4. read the default power constants for phase c by sending 0x0b command on the spi. the chipset will return six bytes, giving the default constants p cc for power constants for phase c. 5. read the value of power as shown by the reference meter for the three phases, say p a , p b , and p c . 6. if the voltage and current on the source have been set at 230 v and high current (60 amps), then the reference meter should display for each phase a value of p ref . using this, calculate new constants as: 7. send command 0x87 followed by p' ca value on the spi. the chipset will accept the values and store these as power constants for phase a. send command 0x89 followed by p' cb value and then command 0xb9 followed by p' cc value. the chipset will store these power constants for phase b and phase c respectively. high gain power calibration the default power constants for all three phases at high gain is 0xaa0. by sending commands such as 0x06, 0x08 and 0x0a on spi, the chipset will send six bytes each, corresponding to phase a, b, and c. procedure 1. power up the meter after setting the voltage at 230 v, cur rent at 5 amps and power factor at unity. 2. read the default power constants for phase a by sending 0x06 command on the spi. the chipset will return six bytes, giving the default constants p ca for power constants for phase a. 3. read the default constants for phase b by sending 0x08 command on the spi. the chipset will return six bytes, giving the default constants p cb for power constants for phase b. 4. read the default power constants for phase c by sending 0x0a command on the spi. the chipset will return six bytes, giving the default constants p cc for power constants for phase c. 5. read the value of power as shown by the reference meter for the three phases, say p a , p b , and p c . = c i i c ia r a ia = c i i c ib r b ib = c i i c ic r c ic = pp p p ca ca ref a = c i i c ia r a ia = c i i c ib r b ib = c i i c ic r c ic = pp p p cb cb ref b = pp p p cc cc ref c
rev. 0 e18e ADSST-EM-2030 6. if the voltage and current on the source have been set at 230 v and low current (5 amps), then the reference meter should display for each phase a value, say p ref . calculate new constants as: 7. send command 0x86 followed by p' ca value on the spi. send command 0x88 followed by p' cb value and then command 0x8a followed by p' cc to save the power constants for high gain. phase compensation the ADSST-EM-2030 uses a phase compensation technique * to take care of the nonlinearities in current transformers. these are two constants, start value (s) and guard value (g). the start value corresponds to the phase shift that is exhibited at high current, and the guard value corresponds to the phase shift at lower currents. the default value for s is 0x08 and for g is 0x20. these constants can be read by sending command 0x15 to the chipset on the spi. the six bytes of data from the chipset will correspond to g a , s a , g b , s b , g c , and s c , in the same sequence as shown in the table xiii. set the current source at i max , voltage source at v nominal , and the phase lag for the current (cos ? = = 10 = 2 hence the correction start value will be: s' a = s a + e p or set the current source at i nominal /2 , voltage source at v nominal , and the phase lag for the current (cos ? = = 10 = e3 hence the correction start value will be: g' a = g a + e p procedure 1. power up the meter after setting the source at 230 v and 60 amps, and power factor at 0.5. 2. read the error shown by the reference meter. round off the error value to the first decimal place and multiply by 10. if the error is negative, then decrease the s value (s a , s b , and s c for phase a, b, and c respectively). if the error is posi- tive, then increase the s value. 3. set the power source at 230 v and 5 amp. read the error shown by the reference meter. round off the error value to the first decimal place and multiply by 10. if the error is negative then decrease the g value (g a , g b , and g c for phase a, b, and c respectively). if the error is positive, then increase the g value. 4. send command 0x95 to the ADSST-EM-2030 chipset followed by the new sequence g' a , s' a , g' b , s' b , g' c , and s' c . = pp p p ca ca ref a = pp p p cb cb ref b = pp p p cc cc ref c * patent pending.
rev. 0 ADSST-EM-2030 e19e outline dimensions 28-lead thin shrink small outline package [tssop] (ru-28) dimensions shown in millimeters 4.50 4.40 4.30 28 15 14 1 9.80 9.70 9.60 6.40 bsc pin 1 seating plane 0.15 0.05 0.30 0.19 0.65 bsc 1.20 max 0.20 0.09 0.75 0.60 0.45 8 0 compliant to jedec standards mo-153ae coplanarity 0.10
c02811e0e11/02(0) printed in u.s.a. e20e

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