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six current channels, one voltage channel energy metering ic data sheet ade7816 rev. 0 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. specifications subject to change without notice. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781.329.4700 www.analog.com fax: 781.461.3113 ?2012 analog devices, inc. all rights reserved. features measures active and reactive energy, sampled waveforms, and current and voltage rms 6 current input channels and 1 voltage channel <0.1% error in active and reactive energy over a dynamic range of 1000:1 supports current transformer and rogowski coil sensors provides instantaneous current and voltage readings angle measurements on all 6 channels 2 khz bandwidth operation reference: 1.2 v (drift 10 ppm/c typical) with external overdrive capability flexible i 2 c, spi, and hsdc serial interfaces general description the ade7816 is a highly accurate, multichannel metering device that is capable of measuring one voltage channel and up to six current channels. it measures line voltage and current and calculates active and reactive energy, as well as instantaneous rms voltage and current. the device incorporates seven sigma-delta (-) adcs with a high accuracy energy measurement core. the six current input channels allow multiple loads to be measured simultaneously. the voltage channel and the six current channels each have a complete signal path allowing for a full range of measurements. each input channel supports a flexible gain stage and is suitable for use with current transformers (cts). six on- chip digital integrators facilitate the use of the rogowski coil sensors. the ade7816 provides access to on-chip meter registers via either the spi or i 2 c interface. a dedicated high speed interface, the high speed data capture (hsdc) port, can be used in conjunction with i 2 c to provide access to real-time adc output information. a full range of power quality information, such as overcurrent, overvoltage, peak, and sag detection, is accessible via the two external interrupt pins, irq0 and irq1 . the ade7816 energy metering ic operates from a 3.3 v supply voltage and is available in a 40-lead lfcsp that is pb free and rohs compliant. functional block diagram iagain pcf_a_coeff hpf vgain hpf lpf awgain awattos avargain avaros x 2 vrms lpf vrmsos x 2 iarms lpf iarmsos 17 39 37 38 36 32 29 3 2 27 28 ref in/out 6 dgnd clkin clkout pga2 15 16 vp vn pga1 7 8 iap ian pull_high pull_low irq0 irq1 sclk/scl mosi/sda miso/hsd ss/hsa 35 hsclk 1 nc 10 nc 11 nc 20 nc 21 nc 30 nc 4 reset hsdc i 2 c spi/i 2 c ade7816 adc adc computational block for total reactive power energy and rms data all channels digital integrator 1.2v ref 9 ibp pga1 12 ibn adc energy and rms calculations see channel a for detailed signal path energy and rms calculations see channel a for detailed signal path energy and rms calculations see channel a for detailed signal path energy and rms calculations see channel a for detailed signal path energy and rms calculations see channel a for detailed signal path 13 icp pga1 14 icn adc 23 idp pga3 adc 22 iep pga3 adc 19 ifp pga3 18 in adc por ldo ldo 5 24 26 25 vdd agnd avdd dvdd 40 nc 34 nc 33 nc 31 nc 10390-001 figure 1.
ade7816 data sheet rev. 0 | page 2 of 48 table of contents features .............................................................................................. 1 ? general description ......................................................................... 1 ? functional block diagram .............................................................. 1 ? revision history ............................................................................... 2 ? specifications..................................................................................... 3 ? timing characteristics ................................................................ 5 ? absolute maximum ratings............................................................ 8 ? thermal resistance ...................................................................... 8 ? esd caution.................................................................................. 8 ? pin configuration and function descriptions............................. 9 ? typical performance characteristics ........................................... 11 ? test circuit ...................................................................................... 14 ? quick start....................................................................................... 16 ? inputs................................................................................................ 17 ? power and ground ..................................................................... 17 ? reference circuit ........................................................................ 17 ? reset ............................................................................................. 17 ? clkin and clkout................................................................ 18 ? analog inputs.............................................................................. 18 ? energy measurements.................................................................... 20 ? starting and stopping the dsp ................................................. 20 ? active energy measurement..................................................... 20 ? reactive energy measurement ................................................. 21 ? line cycle accumulation mode............................................... 22 ? root mean square measurement ............................................. 23 ? no load detection ..................................................................... 23 ? energy calibration ......................................................................... 24 ? channel matching ...................................................................... 24 ? energy gain calibration ........................................................... 24 ? energy offset calibration ......................................................... 24 ? energy phase calibration.......................................................... 25 ? rms offset calibration ............................................................. 25 ? power quality features.................................................................. 26 ? selecting a current channel group ........................................ 26 ? instantaneous waveforms ......................................................... 26 ? zero-crossing detection........................................................... 26 ? peak detection............................................................................ 27 ? overcurrent and overvoltage detection ................................ 27 ? indication of power direction .................................................. 28 ? angle measurements ................................................................. 28 ? period measurement.................................................................. 29 ? voltage sag detection ................................................................ 29 ? setting the sagcyc register................................................... 29 ? setting the saglvl register.................................................... 29 ? voltage sag interrupt ................................................................. 29 ? checksum.................................................................................... 30 ? outputs ............................................................................................ 31 ? interrupts..................................................................................... 31 ? communication ......................................................................... 31 ? registers........................................................................................... 36 ? register protection..................................................................... 36 ? register format .......................................................................... 36 ? register maps.............................................................................. 37 ? outline dimensions ....................................................................... 45 ? ordering guide .......................................................................... 45 ? revision history 2/12revision 0: initial version
data sheet ade7816 rev. 0 | page 3 of 48 specifications vdd = 3.3 v 10%, agnd = dgnd = 0 v, on-chip reference, clkin = 16.384 mhz, t min to t max = ?40c to +85c. table 1. parameter 1 , 2 min typ max unit test conditions/comments accuracy active energy measurement active energy measurement error (per channel) 0.1 % over a dynamic range of 1000 to 1, pga = 1, 2, 4; integrator off 0.2 % over a dynamic range of 3000 to 1, pga = 1, 2, 4; integrator off 0.1 % over a dynamic range of 500 to 1, pga = 8,16; integrator on phase error between channels line frequency = 45 hz to 65 hz, hpf on power factor (pf) = 0.8 capacitive 0.05 degrees phase lead = 37 pf = 0.5 inductive 0.05 degrees phase lag = 60 ac power supply rejection vdd = 3.3 v + 120 mv rms/120 hz, ixp = vp = 100 mv rms energy register variation 0.01 % dc power supply rejection vdd = 3.3 v 330 mv dc energy register variation 0.01 % total active energy measurement bandwidth 2 khz reactive energy measurement reactive energy measurement error (per channel) 0.1 % over a dynamic range of 1000 to 1, pga = 1, 2, 4; integrator off 0.2 % over a dynamic range of 3000 to 1, pga = 1, 2, 4; integrator off 0.1 % over a dynamic range of 500 to 1, pga = 8,16; integrator on phase error between channels line frequency = 45 hz to 65 hz, hpf on pf = 0.8 capacitive 0.05 degrees phase lead = 37 pf = 0.5 inductive 0.05 degrees phase lag = 60 ac power supply rejection vdd = 3.3 v + 120 mv rms/120 hz, ixp = vp = 100 mv rms energy register variation 0.01 % dc power supply rejection vdd = 3.3 v 330 mv dc energy register variation 0.01 % total reactive energy measurement bandwidth 2 khz rms measurements i rms and v rms measurement bandwidth 2 khz i rms and v rms measurement error 0.1 % over a dynamic range of 500 to 1; one second of averaging (100 samples) analog inputs maximum signal levels 500 mv peak single-ended inputs between the following pins: iap and ian, ibp and ibn, icp and icn, idp and in, iep and in, ifp and in. input impedance (dc) iap, ian, ibp, ibn, icp, icn, idp, iep, and ifp pins 400 k in pin 130 k adc offset error 2 mv pga = 1, uncalibrated error, see the terminology section gain error 4 % external 1.2 v reference
ade7816 data sheet rev. 0 | page 4 of 48 parameter 1 , 2 min typ max unit test conditions/comments waveform sampling sampling clkin/2048, 16.384 mhz/2048 = 8 ksps current and voltage channels see the instantaneous waveforms section signal-to-noise ratio, snr 70 db pga = 1 signal-to-noise-and-distortion ratio, sinad 60 db pga = 1 bandwidth (?3 db) 2 khz time interval between channels measurement error 0.3 degrees line frequency = 45 hz to 65 hz, hpf on reference input ref in/out input voltage range 1.1 1.3 v minimum = 1.2 v ? 8%; maximum = 1.2 v + 8% input capacitance 10 pf on-chip reference nominal 1.207 v at the ref in/out pin at t a = 25c reference error 2 mv output impedance 1.2 k temperature coefficient 10 50 ppm/c maximum value across full temperature range of ?40c to +85c clkin, clkout all specifications are for clkin, clkout of 16.384 mhz input clock frequency 16.22 16.384 16.55 mhz crystal equivalent series resistance 30 200 clkin input capacitance 20 pf clkout output capacitance 20 pf logic inputsmosi/sda, sclk/scl, ss /hsa , reset , pull_high, pull_low input high voltage, v inh 2.0 v vdd = 3.3 v 10% input low voltage, v inl 0.8 v vdd = 3.3 v 10% input current, i in ?8.7 a input = 0 v, vdd = 3.3 v 3 a input = vdd = 3.3 v 100 na input = vdd = 3.3 v input capacitance, c in 10 pf logic outputs irq0 , irq1 , miso/hsd vdd = 3.3 v 10% output high voltage, v oh 2.4 v vdd = 3.3 v 10% i source 800 a output low voltage, v ol 0.4 v vdd = 3.3 v 10% i sink 2 ma power supply for specified performance vdd pin 3.0 3.6 v minimum = 3.3 v ? 10%; maximum = 3.3 v + 10% i dd 25 27.8 ma 1 see the typical performance characteristics section. 2 see the terminology section for a definition of the parameters.
data sheet ade7816 rev. 0 | page 5 of 48 timing characteristics vdd = 3.3 v 10%, agnd = dgnd = 0 v, on-chip reference, clkin = 16.384 mhz, t min to t max = ?40c to +85c. note that, within the timing tables and diagrams, the dual function pin names are referenced by the relevant function only; see the pin configuration and function descriptions section for full pin mnemonics and function descriptions. i 2 c-compatible interface timing table 2 i 2 c-compatible interface timing parameters standard mode fast mode parameter symbol min max min max unit scl clock frequency f scl 0 100 0 400 khz hold time (repeated) start condition t hd;sta 4.0 0.6 s low period of scl clock t low 4.7 1.3 s high period of scl clock t high 4.0 0.6 s setup time for repeated start condition t su;sta 4.7 0.6 s data hold time t hd;dat 0 3.45 0 0.9 s data setup time t su;dat 250 100 ns rise time of both sda and scl signals t r 1000 20 300 ns fall time of both sda and scl signals t f 300 20 300 ns setup time for stop condition t su;sto 4.0 0.6 s bus free time between a stop and start condition t buf 4.7 1.3 s pulse width of suppressed spikes t sp n/a 1 50 ns 1 n/a means not applicable. t f t r t hd;dat t hd;sta t high t su;sta t su;dat t r t hd;sta t sp t su;sto t r t buf t low s d a scl start condition repeated start condition stop condition start condition 10390-002 figure 2. i 2 c-compatible in terface timing
ade7816 data sheet rev. 0 | page 6 of 48 spi interface timing table 3. spi interface timing parameters parameter symbol min max unit ss to sclk edge t ss 50 ns sclk period 0.4 4000 1 s sclk low pulse width t sl 175 ns sclk high pulse width t sh 175 ns data output valid after sclk edge t dav 100 ns data input setup time before sclk edge t dsu 100 ns data input hold time after sclk edge t dhd 5 ns data output fall time t df 20 ns data output rise time t dr 20 ns sclk rise time t sr 20 ns sclk fall time t sf 20 ns miso disable after ss rising edge t dis 200 ns ss high after sclk edge t sfs 0 ns 1 guaranteed by design. msb lsb lsb in intermediate bits intermediate bits t sfs t dis t ss t sl t df t sh t dhd t dav t dsu t sr t sf t dr msb in mosi miso sclk ss 10390-003 figure 3. spi interface timing
data sheet ade7816 rev. 0 | page 7 of 48 hsdc interface timing table 4. hsdc interface timing parameter parameter symbol min max unit hsa to hsclk edge t ss 0 ns hsclk period 125 ns hsclk low pulse width t sl 50 ns hsclk high pulse width t sh 50 ns data output valid after hsclk edge t dav 40 ns data output fall time t df 20 ns data output rise time t dr 20 ns hsclk rise time t sr 10 ns hsclk fall time t sf 10 ns hsd disable after hsa rising edge t dis 5 ns hsa high after hsclk edge t sfs 0 ns msb lsb intermediate bits t sfs t dis t ss t sl t df t sh t dav t sr t sf t dr hsd hsclk hsa 10390-004 figure 4. hsdc interface timing load circuit for all timing specifications 2ma i ol 800a i oh 1.6v to output pin c l 50pf 10390-005 figure 5. load circuit for all timing specifications
ade7816 data sheet rev. 0 | page 8 of 48 absolute maximum ratings t a = 25c, unless otherwise noted. table 5. parameter rating vdd to agnd ?0.3 v to +3.7 v vdd to dgnd ?0.3 v to +3.7 v analog input voltage to agnd, iap, ian, ibp, ibn, icp, icn, idp, iep, ifp, in ?2 v to +2 v analog input voltage to vp and vn ?2 v to +2 v reference input voltage to agnd ?0.3 v to vdd + 0.3 v digital input voltage to dgnd ?0.3 v to vdd + 0.3 v digital output voltage to dgnd ?0.3 v to vdd + 0.3 v operating temperature industrial range ?40c to +85c storage temperature range ?65c to +150c junction temperature 150c stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. regarding the temperature profile used in soldering rohs- compliant parts, analog devices, inc., advises that reflow profiles should conform to j-std-20 from jedec. refer to the jedec website for the latest revision. thermal resistance ja is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. table 6. thermal resistance package type ja jc unit 40-lead lfcsp 29.3 1.8 c/w esd caution
data sheet ade7816 rev. 0 | page 9 of 48 pin configuration and fu nction descriptions notes 1. nc = no connect. these pins are not connected internally and should be left floating. 2. create a similar pad on the pcb under the exposed pad. solder the exposed pad to the pad on the pcb to confer mechanical strength to the package. do not connect the pads to agnd. 11 nc 12 ibn 13 icp 15 vp 17 ref in/out 16 vn 18 in 19 ifp 20 nc 14 icn nc pull_high pull_low reset dvdd dgnd iap ian ibp nc idp avdd agnd vdd clkin clkout irq0 nc iep nc 33 nc 34 nc 35 hsclk 36 sclk/scl 37 miso/hsd 38 mosi/sda 39 ss/hsa 40 nc 32 ir q1 31 nc 1 2 3 4 5 6 7 8 9 10 23 24 25 26 27 28 29 30 22 21 ade7816 top view (not to scale) 10390-006 figure 6. pin configuration table 7. pin function descriptions pin no. mnemonic description 1, 10, 11, 20, 21, 30, 31, 33, 34, 40 nc no connect. these pins are not connected internally and should be left floating. 2 pull_high connect this pin to vdd for proper operation. 3 pull_low connect this pin to agnd for proper operation. 4 reset active low reset input. hold this pin low for at least 10 s to trigger a hardware reset. 5 dvdd on-chip 2.5 v digital ldo access. do not connect any extern al active circuitry to this pin. decouple this pin with a 4.7 f capacitor in parallel with a ceramic 220 nf capacitor. 6 dgnd ground reference. this pin provides the ground reference for the digital circuitry. 7, 8 iap, ian analog inputs for current channel a. this channel is us ed with the current transducers and is referenced in this data sheet as current channel a. connect these in puts in a single-ended configuration with a maximum signal level of 0.5 v with respect to ian. 9, 12 ibp, ibn analog inputs for current channel b. this channel is used with the curren t transducers and is referenced in this data sheet as current channel b. connect these in puts in a single-ended configuration with a maximum signal level of 0.5 v with respect to ibn. 13, 14 icp, icn analog inputs for current channel c. this channel is used with the curren t transducers and is referenced in this data sheet as current channel c. connect these in puts in a single-ended configuration with a maximum signal level of 0.5 v with respect to icn. 15, 16 vp, vn analog inputs for the voltage channel. this channel is used with the voltage transducer and is referenced as the voltage channel in this data sheet. connect these inputs in a single-ended configuration with a maximum signal level of 0.5 v with respect to vn. this channel also has an internal pga. 17 ref in/out on-chip voltage reference access. the on-chip reference has a nominal value of 1.2 v. an external reference source with 1.2 v 8% can also be connected at this pi n. in either case, decouple this pin to agnd with a 4.7 f capacitor in parallel with a ceramic 100 nf capacitor. 18 in analog input common pin for current channel d, current channel e, and current channel f. see the pin descriptions for pin 19, pin 22, and pin 23 for more details. 19 ifp analog input for current channel f. this channel is used with the current tr ansducers and is referenced in this data sheet as current channel f. connect this input in a single-ended configuration with a maximum signal level of 0.5 v with respect to in. 22 iep analog input for current channel e. th is channel is used with the curren t transducers and is referenced in this data sheet as current channel e. connect this input in a single-ended configuration with a maximum signal level of 0.5 v with respect to in. 23 idp analog input for current channel d. this channel is us ed with the current transducers and is referenced in this data sheet as current channel d. connect this input in a single-ended configuration with a maximum signal level of 0.5 v with respect to in.
ade7816 data sheet rev. 0 | page 10 of 48 pin no. mnemonic description 24 avdd on-chip 2.5 v analog low dropout (ldo) regulator access . do not connect external active circuitry to this pin. decouple this pin with a 4.7 f capacitor in parallel with a ceramic 220 nf capacitor. 25 agnd ground reference. this pin provides the ground reference for the analog circuitry. tie this pin to the analog ground plane or to the quietest gr ound reference in the system. use this quiet ground reference for all analog circuitry, such as antialiasing fi lters and current and voltage transducers. 26 vdd supply voltage. this pin provides th e supply voltage and should be set at 3.3 v 10% for specified operation. decouple this pin to agnd with a 10 f capacitor in parallel with a ceramic 100 nf capacitor. 27 clkin master clock. an external clock can be provided at th is logic input. alternatively, a parallel resonant at-cut crystal can be connected across clkin and cl kout to provide a clock source for the ade7816 . the clock frequency for specified operation is 16.384 mhz. use ceramic load capacitors of a few tens of picofarads (pf) with the gate oscillator circuit. refe r to the crystal manufacturer data sheet for load capacitance requirements. 28 clkout a crystal can be connected across this pin and clkin (as stated in the description for pin 27) to provide a clock source for the ade7816 . the clkout pin can drive one cmos load when either an external clock is supplied at clkin or a crystal is being used. 29, 32 irq0 , irq1 interrupt request outputs. these are active low logi c outputs. see the communication section for a detailed presentation of the events that can trigger interrupts. 35 hsclk serial clock output for the hsdc port. 36 sclk/scl serial clock input for the spi port/serial clock input for the i 2 c port. all serial data transfers are synchronized to this clock (see the serial interfaces section). this pin has a schmidt trigger input for use with a clock source that has a slow edge transition time (for example, opto-isolator outputs). 37 miso/hsd data output for spi port/data output for hsdc port. 38 mosi/sda data input for spi port/data output for i 2 c port. 39 ss /hsa slave select for spi port/hsdc port active. ep exposed pad exposed pad. create a similar pad on the pcb under th e exposed pad. solder the exposed pad to the pad on the pcb to confer mechanical strength to th e package. do not connect the pads to agnd.
data sheet ade7816 rev. 0 | page 11 of 48 typical performance characteristics 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.01 0.1 1 10 100 error (% of reading) current channel (% of full scale) +85c +25c ?40c 10390-101 figure 7. active energy error as a percentage of reading (gain = 1, power factor = 1) over temperature with internal reference, integrator off 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.01 0.1 1 10 100 error (% of reading) current channel (% of full scale) pf = +0.5 pf = +1 pf = ?0.5 10390-102 figure 8. active energy error as a percentage of reading (gain = 1, temperature = 25c) over power factor with internal reference, integrator off 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.01 0.1 1 10 100 error (% of reading) current channel (% of full scale) vdd = 2.97v vdd = 3.30v vdd = 3.63v 10390-103 figure 9. active energy error as a percentage of reading (gain = 1, temperature = 25c, power factor = 1) over supply voltage with internal reference, integrator off 0.5 ?0.5 ?0.4 ?0.3 ?0.2 ?0.1 0 0.1 0.2 0.3 0.4 45 65 60 55 50 error (% of reading) frequency (hz) pf = +0.5 pf = +1 pf = ?0.5 10390-104 figure 10. active energy error as a percentage of reading (gain = 1, temperature = 25c) over frequency and power factor with internal reference, integrator off 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.01 0.1 1 10 100 error (% of reading) current channel (% of full scale) +85c +25c ?40c 10390-105 figure 11. reactive energy error as a percentage of reading (gain = 1, power factor = 0) over temperature with internal reference, integrator off 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.01 0.1 1 10 100 error (% of reading) current channel (% of full scale) pf = +0.87 pf = 0 pf = ?0.87 10390-106 figure 12. reactive energy error as a percentage of reading (gain = 1, temperature = 25c) over power factor with internal reference, integrator off
ade7816 data sheet rev. 0 | page 12 of 48 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.01 0.1 1 10 100 error (% of reading) current channel (% of full scale) vdd = 3.30v vdd = 3.63v vdd = 2.97v 10390-107 figure 13. reactive energy error as a percentage of reading (gain = 1, temperature = 25c, power factor = 0) over supply voltage with internal reference, integrator off 0.5 ?0.5 ?0.4 ?0.3 ?0.2 ?0.1 0 0.1 0.2 0.3 0.4 45 65 60 55 50 error (% of reading) frequency (hz) pf = +0.87 pf = 0 pf = ?0.87 10390-108 figure 14. reactive energy error as a percentage of reading (gain = 1, temperature = 25c) over frequency and power factor with internal reference 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.1 1 10 100 error (% of reading) current channel (% of full scale) 10390-109 figure 15. i rms error as a percentage of reading (gain = 1, temperature = 25c, power factor = 1) with internal reference, integrator off 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.1 1 10 100 error (% of reading) current channel (% of full scale) 10390-110 figure 16. v rms error as a percentage of reading (gain = 1, temperature = 25c, power factor = 1) with internal reference, integrator off 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.1 1 10 100 error (% of reading) current channel (% of full scale) +85c +25c ?40c 10390-111 figure 17. active energy error as a percentage of reading (gain = 16, power factor = 1) over temperature with internal reference, integrator on 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.1 1 10 100 error (% of reading) current channel (% of full scale) pf = +0.5 pf = 1 pf = ?0.5 10390-112 figure 18. active energy error as a percentage of reading (gain = 16, temperature = 25c) over power factor with internal reference, integrator on
data sheet ade7816 rev. 0 | page 13 of 48 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.1 1 10 100 error (% of reading) current channel (% of full scale) +85c +25c ?40c 10390-113 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.1 1 10 100 error (% of reading) current channel (% of full scale) 10390-115 figure 19. reactive energy error as a percentage of reading (gain = 16, power factor = 0) over temperature with internal reference, integrator on figure 21. i rms error as a percentage of reading (gain = 16, temperature = 25c, power factor = 1) with internal reference, integrator on 1.0 ?1.0 ?0.8 ?0.6 ?0.4 ?0.2 0 0.2 0.4 0.6 0.8 0.1 1 10 100 error (% of reading) current channel (% of full scale) pf = +0.87 pf = 0 pf = ?0.87 10390-114 figure 20. reactive energy error as a percentage of reading (gain = 16, temperature = 25c) over power factor with internal reference, integrator on
ade7816 data sheet rev. 0 | page 14 of 48 test circuit 0.22f 4.7f mosi/sda miso/hsd sclk/scl reset 4 39 38 37 36 ade7816 24 26 5 avdd vdd dvdd 6 25 dgnd agnd pull_high 2 pull_low 3 hsclk 35 nc 1 nc 10 nc 11 nc 20 nc 21 nc 30 nc 31 nc 33 nc 34 nc 40 0.22f 4.7f + + ref in/out clkout clkin 17 28 27 0.1f 4.7f 20pf + 20pf 16.384mhz 10k? 3.3v 3.3v 1f ss/hsa 32 irq1 29 irq0 iap 7 ian 8 ibp 9 ibn 12 icp 13 icn 14 ifp 19 iep 22 idp 23 in 18 vn 16 vp 15 10390-007 figure 22. test circuit
data sheet ade7816 rev. 0 | page 15 of 48 terminology measurement error the error associated with the energy measurement made by the ade7816 is defined by the following equation: measurement error = %100 ? ? energytrue energytrue ade7816 by registered energy phase error between channels the high-pass filter (hpf) and digital integrator introduce a slight phase mismatch between the current channels and the voltage channel. the all digital design ensures that the phase matching between the current channels and voltage channel in all three phases is within 0.1 over a range of 45 hz to 65 hz and 0.2 over a range of 40 hz to 1 khz. this internal phase mismatch can be combined with the external phase error (from current sensor or component tolerance) and calibrated with the phase calibration registers. power supply rejection (psr) psr quantifies the ade7816 measurement error as a percentage of reading when the power supplies are varied. for the ac psr measurement, a reading at nominal supplies (3.3 v) is taken. a second reading is obtained with the same input signal levels when an ac signal (120 mv rms at 100 hz) is introduced onto the supplies. any error introduced by this ac signal is expressed as a percentage of reading (see the measurement error definition). for the dc psr measurement, a reading at nominal supplies (3.3 v) is taken. a second reading is obtained with the same input signal levels when the power supplies are varied 10%. any error introduced is expressed as a percentage of the reading. adc offset error adc offset error refers to the dc offset that is associated with the analog inputs to the adcs. it means that , with the analog inputs connected to agnd, the adcs still see a dc analog input signal. the magnitude of the offset depends on the gain and input range selection (see the typical performance characteristics section). however, the hpf removes the offset from the current channels and voltage channel, and the power calculation remains unaffected by this offset. gain error the gain error in the adcs of the ade7816 is defined as the difference between the measured adc output code (minus the offset) and the ideal output code. the difference is expressed as a percentage of the ideal code.
ade7816 data sheet rev. 0 | page 16 of 48 quick start this section outlines the procedure for powering up and initializing the ade7816 . figure 23 shows a flow diagram of the initialization steps. for detailed information, refer to the section of the data sheet that pertains to each step, as indicated in figure 23 . after power is supplied to the ade7816 and communication is established, a set of registers must be written (see figure 23 ). table 8 lists details about each register. the registers listed in table 8 are essential for correct operation. after these registers are set, enable any meter-specific features before enabling the dsp to begin the energy calculations. note that the final register should be written 3 times to clear the buffer (see starting and stopping the dsp section) wthr1 = 0x000002 wthr0 = 0x000000 varthr1 = 0x000002 varthr0 = 0x000000 pcf_a_coeff = 0x400ca4 (50hz) pcf_b_coeff = 0x400ca4 (50hz) pcf_c_coeff = 0x400ca4 (50hz) pcf_d_coeff = 0x400ca4 (50hz) pcf_e_coeff = 0x400ca4 (50hz) pcf_f_coeff = 0x400ca4 (50hz) dicoeff = 0xfff8000 power up the ade7816 (see power and ground section) initialization complete enable the energy metering dsp (see starting and stopping the dsp section) write required register defaults set and lock communication mode (see communication section) configure meter specific interrupts, power quality features, and calibrate (see the interrupts, power quality features, and energy calibration sections) 10390-008 figure 23. quick start table 8. required register defaults register address register name register description required value reference information 0x43ab wthr1 threshold register for active energy 0x000002 refer to the active energy threshold section. 0x43ac wthr0 threshold register for active energy 0x000000 refer to the active energy threshold section. 0x43ad varthr1 threshold register for reactive energy 0x000002 refer to the reactive energy threshold section. 0x43ae varthr0 threshold register for reactive energy 0x000000 refer to the reactive energy threshold section. 0x43b1 pcf_a_coeff phase calibration fo r current channel a 0x400ca4 (50 hz) refer to the energy phase calibration section. 0x43b2 pcf_b_coeff phase calibration fo r current channel b 0x400ca4 (50 hz) refer to the energy phase calibration section. 0x43b3 pcf_c_coeff phase calibration fo r current channel c 0x400ca4 (50 hz) refer to the energy phase calibration section. 0x43b4 pcf_d_coeff phase calibration fo r current channel d 0x400ca4 (50 hz) refer to the energy phase calibration section. 0x43b5 pcf_e_coeff phase calibration fo r current channel e 0x400ca4 (50 hz) refer to the energy phase calibration section. 0x43b6 pcf_f_coeff phase calibration fo r current channel f 0x400ca4 (50 hz) refer to the energy phase calibration section. 0x4388 dicoeff digital integrator algorithm; required only if using di/dt sensors 0xfff8000 refer to the digital integrator section.
data sheet ade7816 rev. 0 | page 17 of 48 inputs the following section provides details on the ade7816 input connections that are required for correct functionality. power and ground vdd and agnd, dgnd to p ower t he ade7816 , a 3.3 v dc input voltage should be provided between the vdd pin and the agnd and dgnd pins. in addition, the pull_high and pull_low pins must be connected to 3.3 v and agnd, respectively. this configuration is shown in figure 24 . 0.22f 4.7f 24 26 5 avdd vdd dvdd pull_high 2 pull_low 3 0.22f 4.7f + + 3.3 v 3.3v 10390-009 figure 24. applying power to the ade7816 the ade7816 contains an on-chip power supply monitor that supervises the power supply (vdd). when the voltage applied to the vdd pin is below 2 v 10%, the chip is in an inactive state. after vdd crosses the 2 v 10% threshold, the power supply monitor keeps the ade7816 in an inactive state for an additional 26 ms. this time delay allows vdd to reach the minimum specified operating voltage of 3.3 v ? 10%. when the minimum specified operating voltage is met and the pull_high and pull_low pins are tied to vdd and agnd, respectively, the internal circuitry is enabled. this process is accomplished in approximately 40 ms. when the start-up sequence is complete and the ade7816 is ready to receive communication from a microcontroller, the rstdone flag is set in the status1 register (address 0xe503). an external interrupt is triggered on the irq1 pin. the rstdone interrupt is enabled by default and cannot be disabled; therefore, an external interrupt always occurs at the end of a power-up procedure or hardware or software reset. it is highly recommended that the rstdone interrupt be used by the microcontroller to gate the first communication with the ade7816 . if the interrupt is not used, a timeout can be imple- mented. however, because the start-up sequence can vary from part to part and over temperature, a timeout of a least 100 ms is recommended. the rstdone interrupt provides the most time- efficient way of monitoring the completion of the ade7816 start-up sequence. the avdd and dvdd output pins provide access to the on- chip analog and digital ldos. when the ade7816 is fully powered up, these pins are at 2.5 v. if the internal reference is being used, the ref in/out pin outputs 1.2 v (see the reference circuit section). when the start-up sequence is complete, all registers are at their default value, and the i 2 c port is the active serial port. commu- nication with the ade7816 can begin. see the communication section for more details. to start the energy and rms computations, the internal dsp must be powered up after all configuration registers are set to their desired values. the dsp is started by setting the run register (address 0xe228) to 0x0001. see the starting and stopping the dsp section for more information. reference circuit ref in/out the nominal reference voltage at the ref in/out pin is 1.2 v 0.075%. the ref in/out pin can be overdriven by an external 1.2 v reference source. if bit 0 (extrefen) in the config2 register (address 0xec01) is cleared to 0 (the default value), the ade7816 uses the internal voltage reference. if bit 0 is set to 1, the external voltage reference is used. the voltage of the ade7816 internal reference drifts slightly with temperature; see the specifications section for the temperature coefficient specification (in ppm/c). the value of the temperature drift varies from part to part. because the reference is used for all adcs, any x% drift in the reference results in a 2x% deviation of the meter accuracy. reset hardware reset to initiate a hardware reset of the ade7816 , the reset pin must be pulled low for at least 10 s. after the reset pin returns high, all registers return to their default values. the signals the end of the transition period by triggering the ade7816 irq1 interrupt pin low and setting bit 15 (rstdone) in the status1 register to 1. this bit is set to 0 during the transition period and changes to 1 when the transition ends. software reset functionality bit 7 (swrst) in the config register (address 0xe618) manages the software reset functionality in the ade7816 . the default value of this bit is 0. if bit 7 is set to 1, the ade7816 enters the software reset state. in this state, all internal registers are set to their default values, with the exception of the config2 register, which retains its existing value. in addition, the choice of which serial port is in use (i 2 c or spi) remains unchanged if the lock-in procedure was executed previously (see the communication s ection for details). when the software reset ends, bit 7 (swrst) in the config register is cleared to 0, the irq1 interrupt pin is set low, and bit 15 (rstdone) in the status1 register is set to 1. rstdone is set to 0 during the transition period and changes to 1 when the transition ends. it is recommended that all meters be designed to have both software and hardware reset capability.
ade7816 data sheet rev. 0 | page 18 of 48 clkin and clkout an external clock or parallel resonant crystal is required to clock the ade7816 . if an external clock source is being used, it should be connected to the clkin pin. the required clock frequency for specified operation is 16.384 mhz. alternatively, a parallel resonant at-cut crystal can be connected across the clkin and clkout pins. the ade7816 has no internal load capacitance and, therefore, load capacitors based on the data sheet of the crystal manufacturer should be added on each pin. analog inputs input pins the ade7816 has seven analog inputs that form six current channels and one voltage channel. current channel a, current channel b, and current channel c each consist of a pair of dif- ferential input pins: iap and ian, ibp and ibn, and icp and icn. current channel d, current channel e, and current channel f all share a common reference, in, and, therefore, are single-ended. for consistency, it is recommended that all six current inputs be connected in a single-ended configuration (see figure 26 and figure 27). the voltage channel is a fully differential input that consists of a pair of inputs: vp and vn. the voltage channel is typically connected in a single-ended configuration. the maximum input voltage that should be applied to any input channel is 500 mv. the maximum common-mode signal that is allowed on the inputs is 25 mv. figure 25 shows a schematic of the inputs and their relation to the maximum common-mode voltage. vn vp v cm v 1 + 500m v v cm v 1 differential input v 1 + v 2 = 500mv max peak common mode v cm = 25mv max ? 500m v 10390-010 figure 25. maximum input level pga gain the ade7816 has three internal pga gain amplifiers that can be used to amplify the input signals by 2, 4, 8 or 16. the pga gain stage is often required when using a current sensor that produces a low output voltage, such as rogowski coils. pga1 affects current channel a, current channel b, and current channel c and is controlled by bits[2:0] (pga1) of the gain register (address 0xe60f). pga2 affects the voltage channel and is controlled by bits[5:3] (pga2) of the gain register. pga3 affects current channel d, current channel e, and current channel f and is controlled by bits[8:6] (pga3) of the gain register. table 9 lists details on how the pga gain affects the full-scale input voltage. table 9. pga gain gain full-scale single-ended input (mv) gain register (address 0xe60f) pga1[2:0] pga2[5:3] pga3[8:6] 1 500 000 000 000 2 250 001 001 001 4 125 010 010 010 8 62.5 011 011 011 16 31.25 100 100 100 digital integrator the ade7816 includes a digital integrator that must be enabled when using a di/dt sensor such as a rogowski coil. this integrator is enabled by setting the inten bit (bit 0) of the config register (address 0xe618) to 1. when using the digital integrator, the dicoeff register (address 0x4388) should be written to 0xfff8000. for more details on the theory behind the digital integrator, refer to the an-1137 application note.
data sheet ade7816 rev. 0 | page 19 of 48 antialiasing filters each analog input pin requires that a simple rc filter be connected to the input. the role of the rc filter is to prevent aliasing. the aliasing effect is caused by frequency components (which are higher than half the sampling rate of the adc) folding back and appearing in the sampled signal at a frequency that is below half the sampling rate. aliasing is an artifact of all sampled systems. for conventional current sensors, it is recommended that one rc filter with a corner frequency of 5 khz be used for the attenuation to be sufficiently high at the sampling frequency of 1.024 mhz. the 20 db per decade attenuation of this filter is usually sufficient to eliminate the effects of aliasing for conventional current sensors (see figure 26 ). load phase ade7816 1k ? 1k ? 22nf 22nf iap ian rb current transformer 10390-011 figure 26. current transformer input connections however, a di/dt sensor, such as a rogowski coil, has a 20 db per decade gain. this neutralizes the 20 db per decade attenuation produced by the low-pass filter (lpf). therefore, when using a di/dt sensor, a second pole is required. one simple approach is to cascade one additional rc filter, thereby producing a ?40 db per decade attenuation (see figure 27 ). load phase ade7816 1k? 1k? 22nf 22nf 100 ? 100 ? 22nf 22nf iap ian rogowski coil 10390-012 figure 27. rogowski coil input connections
ade7816 data sheet rev. 0 | page 20 of 48 energy measurements this section describes the energy measurements available in the ade7816 . for information about the theory behind these measurements, refer to the an-1137 application note. starting and stopping the dsp to obtain energy measurements, the internal processor must first be started by setting the run register (address 0xe228) to 0x0001. it is recommended that all registers be initialized before starting the dsp and that the last register in the queue be written three times to flush the pipeline. when this procedure is complete, the dsp should be started. there is no reason to stop the dsp, once started, because all of the registers can be modified while the dsp is running. the dsp can be stopped, however, by writing 0x0000 to the run register. within the dsp core, there is a two-stage pipeline. this means that when a single register must be initialized, two or more writes are required to ensure that the value has been written. if two or more registers must be initialized, the last register must be written two more times to ensure that the value is written into the ram. it is recommended that the last register be written three times to ensure successful communication. see the register protection section for details on protecting these registers. active energy measurement definition of active pow er and active energy active power is the product of voltage and current and is the power dissipated in a purely resistive load. active energy is the accumulation of active power over time and is measured in watts. the average power over an integral number of line cycles (n) is given by the following expression: p = nt dttp nt 0 )( 1 = vi (1) where: v is the rms voltage. i is the rms current. p is the active or real power. t is the line cycle period. active energy registers the ade7816 has six active energy registers, where the active energy is accumulated for each of the six channels separately: awatthr (address 0xe400), bwatthr (address 0xe401), cwatthr (address 0xe402), dwatthr (address 0xe403), ewatthr (address 0xe404) and fwatthr (address 0xe405). all active energy registers are in 32-bit, signed format. the ade7816 accumulates both positive and negative power. negative power indicates that the angle between the voltage and current is greater than 90, and power is being injected back into the grid. the ade7816 provides a signed accumulation of the power; positive power is added and negative power is subtracted. figure 28 shows the configurations of the active energy signal path. active energy threshold the ade7816 accumulates energy in two steps (see figure 28 ). the first step occurs internally, using the two threshold registers, wthr1 (address 0x43ab) and wthr0 (address 0x43ac). these registers make up the most significant and least significant 24 bits, respectively, of an internal threshold register that is used to control the frequency at which the external xwatthr registers are updated. the wthr1 and wthr0 registers affect all six active energy measurements. for standard operation, the wthr1 regi- ster should be set to 0x2 and the wthr0 register set to 0x0. thus, the update rate of the xwatthr registers is set to slightly below the maximum of 8 khz with full-scale inputs. if the rate at which energy is accumulated in the xwatthr registers must be reduced, the wthr1and wthr0 registers can be modified. threshold = 0x2000000 (khz) khz8 rate update required (2) note that the maximum output with full scale inputs is 8 khz. do not adjust the threshold to try to produce more than 8 khz. such an adjustment may result in saturation of the output frequency and, therefore, a loss of accuracy. the second stage of the accumulation occurs in the external registers, xwatthr. with the recommended values provided in equation 2, the energy updates at a rate of 8 khz with full- scale inputs (see figure 28 ). energy accumulation and register roll-over as shown in equation 2, the active energy accumulates at a maxi- mum rate of 8 khz with full-scale inputs. the maximum positive value that the 32-bit, signed xwatthr registers can store before they overflow is 0x7fffffff. a ssuming steady accumulation with full-scale inputs, the accumulation time is time = 0x7fffffff 125 s = 74 hr, 33 min, 55 sec vgain hpf iagain digital integrator hpf va ia awgain awattos pcf_a_coeff accumulator wthr[47:0] awatthr[31:0] 32-bit register lpf 10390-013 figure 28. active energy signal path
data sheet ade7816 rev. 0 | page 21 of 48 the content of the active energy register overflows from full-scale positive (0x7fffffff) to full- scale negative (0x80000000) and continues to increase in value when the active power is positive. conversely, if the active power is negative, the energy register underflows from full-scale negative (0x80000000) to full-scale positive (0x7fffffff) and continue s decreasing in value. bit 0 (aehf1) in the status0 register (address 0xe502) is set when bit 30 in the awatthr, bwatthr, or cwatthr register changes, signifying that one of these registers is half full. simi- larly, bit 1 (aehf2) in the stat us0 register is set when bit 30 in the dwatthr, ewatthr, or fwatthr register changes, signifying that one of these registers is half full. setting bit 6 (rstread) in the lcycmode register (address 0xe702) enables a read-with-reset for all watt-hour accumulation registers. when this bit is set, all energy accu- mulation registers are set to 0 following a read operation. reactive energy measurement definition of reactive pow er and reactive energy reactive power is the product of the voltage and current when all harmonic components of one of these signals are phase shifted by 90. reactive power is the power dissipated in an induc-tive or capacitive load and is measured as volt-ampere reactive (var). reactive energy is the accumulation of reactive power over time. rp = () nt dttrp nt 0 1 = vi sin( ) (3) where: v is the rms voltage. i is the rms current. rp is the reactive or real power. t is the line cycle period. reactive energy registers the ade7816 has six reactive energy registers that accumulate active energy for each of the six channels separately: avarhr (address 0xe406), bvarhr (address 0xe407), cvarhr (address 0xe408), dvarhr (address 0xe409), evarhr (address 0xe40a), and fvarhr (address 0xe40b). all reactive energy registers are in 32-bit, signed format. the ade7816 accumulates both positive and negative reactive power. negative reactive power indicates that the current is leading the voltage by up to 180. the ade7816 provides a signed accumulation of the power, where positive power is added and negative is subtracted. reactive energy threshold the ade7816 accumulates energy in two steps. the first is done internally using the threshold registers, varthr1 (address 0x43ad) and varthr0 (address 0x43ae). these registers make up the most significant and least significant 24 bits, respectively, of an internal threshold register that is used to control the frequency at which the external xvarhr registers are updated. t h e va rt h r 1 a n d va rt h r 0 r e g i s t e r s a f f e c t a l l s i x r e a c t i v e energy measurements. for standard operation, the varthr1 register should be set to 0x2 and the varthr0 register set to 0x0. this sets the update rate of the xvarhr registers to the maximum of 8 khz with full-scale inputs. if the rate at which energy is accumulated in the xvarhr registers must be reduced, varthr1 and varthr0 can be modified as follows: threshold = 0x2000000 (khz) khz8 rate update required (4) note that the maximum output with full scale inputs is 8 khz. the threshold should not be adjusted to try to produce more than 8 khz. such an adjustment could result in saturation of the output frequency and, therefore, a loss of accuracy. the second stage of the accumulation is done in the external registers, xvarhr. with the recommended values provided in equation 4, the reactive energy updates at a rate of 8 khz with full-scale inputs (see figure 29 ). reactive energy accumulation and register roll-over the reactive energy accumulates at a maximum rate of 8 khz with full-scale inputs. the maximum positive value that the 32-bit, signed xvarhr registers can store before they overflow is 0x7fffffff. assuming steady a ccumulation with full-scale reactive energy inputs, the accumulation time is time = 0x7fffffff 125 s = 74 hr, 33 min, 55 sec conversely, if the reactive power is negative, the energy register underflows from full-scale negative (0x80000000) to full-scale positive (0x7fffffff) and continue s decreasing in value. bit 2 (rehf1) in the status0 register is set when bit 30 of the avarhr, bvarhr, or cvarhr register changes, signifying that one of these registers is ha lf full. similarly, bit 3 (rehf2) in the status0 register is set when bit 30 of the dvarhr, evarhr, or fvarhr register changes, signifying that one of these registers is half full. vgain hpf iagain digital integrator hpf va ia pcf_a_coeff avargain avaros accumulator varthr[47:0] avarhr[31:0] 32-bit register total reactive power algorithm 10390-014 figure 29. reactive energy signal path
ade7816 data sheet rev. 0 | page 22 of 48 the reactive energy register content overflows from full-scale positive (0x7fffffff) to full- scale negative (0x80000000) and continues to increase in value when the reactive power is positive. setting bit 6 (rstread) of the lcycmode (address 0xe702) register enables a read-with-rese t for all reactive energy accu- mulation registers. when this bit is set, all energy accumulation registers are set to 0 following a read operation. line cycle accumulation mode in the active and reactive line cycle accumulation mode, the energy accumulation of the ade7816 is synchronized to the voltage channel zero crossing, so that the active and reactive energy can be accumulated over an integral number of half line cycles. this feature is available for the active and reactive energy accumulation on all six channels. the advantage of summing the active and reactive energy over an integral number of half line cycles is that the sinusoidal component of the energy is reduced to 0. this eliminates any ripple in the energy calculation. accurate energy is calculated in a shorter time because the integration period can be shortened. the line cycle accumulation mode can be used for fast calibration and to obtain the average power over a specified time period. figure 30 shows a diagram of the active energy line cycle accumulation mode signal path. active and reactive energy line cycle accumulation modes are disabled by default and can be enabled on all six channels by setting bit 0 (lwatt) and bit 1 (lvar), respectively, in the lcycmode register. bit 3 (zx_sel) of the lcycmode register must also be set to enable the voltage channel zero-crossing counter to be used in the line cycle accumulation measurement. the accumulation time should be written to the linecyc register (address 0xe60c) as an integer number of half line cycles. the ade7816 can accumulate energy for up to 65,535 half line cycles. this equates to an accumulation period of approximately 655 sec with 50 hz inputs, and 546 sec with 60 hz inputs. the number of half line cycles written to the linecyc register is used for the active and reactive line cycle accumulation on all six channels. at the end of a line cycle accumulation period, the xwatthr and xvarhr registers are updated and the lenergy flag is set in the status0 register (address 0xe502). if the lenergy bit in the mask0 register (address 0xe50a) is set, an external interrupt is issued on the irq0 pin. another accu- mulation cycle begins immediately, as long as the lwatt and lvar bits in the lcycmode register remain set. the contents of the xwatthr and xvarhr registers are updated synchronous to the lenergy flag. the xwatthr and xvarhr registers hold their current values until the end of the next line cycle period, when the contents are replaced with the new reading (see figure 30 and figure 31 ). when using the line cycle accu- mulation mode, bit 6 (rstread) of the lcycmode register should be set to logic 0 because the read-with-reset function of the energy registers is not available in this mode. note that, when line cycle accumulation mode is first enabled, the reading after the first lenergy flag should be ignored because it may be inaccurate. this inaccuracy is due to the line cycle accumulation mode not being synchronized to the zero crossing. as a result, the first reading may not be taken over a complete number of half line cycles. after the first line cycle accumulation is completed, all successive readings are correct. xwgain internal accumulation wthr[48:0] xwattos 23 xwatthr 0 lpf_zx output from voltage channel adc output from lpf zero-crossing detection calibration control 15 0 linecyc + + 48 0 10390-015 figure 30. line cycle accumulation for xwatthr xvargain internal accumulation varthr[48:0] xvaros 23 xvarhr 0 lpf_zx output from voltage channel adc output from reactive power algorithm zero-crossing detection calibration control 15 0 linecyc + + 48 0 10390-200 figure 31. line cycle accumulation for xvarhr
data sheet ade7816 rev. 0 | page 23 of 48 root mean square measurement root mean square (rms) is a measurement of the magnitude of an ac signal. specifically, the rms of an ac signal is equal to the amount of dc required to produce an equivalent amount of power in the load. the ade7816 provides rms measurements on the six current channels and the voltage channel simultaneously. these measurements have a settling time of approximately 440 ms with the integrator off and 500 ms with the integrator on. the registers are updated every 125 s. the rms value is measured over a 2 khz bandwidth. the 24-bit, unsigned voltage rms measurement is available in the vrms register (address 0x43c0). similarly, the six current channel rms measurements are available in the iarms (address 0x43c1), ibrms (address 0x43c2), icrms (address 0x43c3), idrms (address 0x43c4), ierms (0x43c5), and ifrms (address 0x43c6) registers. all registers are updated at a rate of 8 khz. figure 32 shows the ixrms signal path. a similar signal path is used on the voltage channel to compute the vrms measurement. due to nonidealities in the internal filtering, it is recommended that the ixrms registers be read synchronously to the zero- crossing signal (see the zero-crossing detection section). this helps to stabilize reading-to-reading variation by removing the effect of any 2 ripple that is present on the rms measurement. with the specified full-scale analog input signal of 0.5 v, the rms value of a sinusoidal signal is 4,191,910 (0x3ff6a6), independent of line frequency. if the integrator is enabled on the current channels, the equivalent current rms value of a full- scale sinusoidal signal at 50 hz is 4,191,910 (0x3ff6a6). at 60 hz, it is 3,493,258 (0x354d8a). no load detection the ade7816 includes a no load detection feature that eliminates meter creep. meter creep is defined as excess energy that is accumulated by the meter when there is no load attached. the ade7816 warns of this condition and stops energy accumulation if the energy falls below a programmable threshold. the ade7816 includes a no load feature on the active and reactive energy measurements. this allows a true no load condition to be detected. the no load condition is triggered when the absolute values of the active and reactive powers are less than or equal to a thresh- old that is specified in the apnoload (address 0x43af) and varnoload (address 0x43b0) registers. when in the no load condition, the active and re active energies are no longer accumulated in the energy registers. note that each of the six channels has a separate no load circuit. setting the no load thresholds the apnoload and varnoload registers are compared to the active and reactive powers, respectively, to set the no load threshold. with full-scale inputs on both the current and voltage channel, the maximum power is 0x1ff6a6b. the no load threshold should, therefore, be set with respect to this maxi- mum power, as follows: apnoload = (5) 0x1ff6a6b v % of full_scale i (noload)% of full_scale for example, if the nominal voltage is set to 50% of full scale and the current channel no load threshold is required to be at 0.01% of full scale, the apnoload threshold is apnoload = 0x1ff6a6b 50% 0.01% = 0x68c (6) the varnoload register is usually set to the same value as that of the apnoload register. when the apnoload and varnoload registers are set to negative values, the no load detection circuit is disabled. bit 0 (nload1) in the status1 register (address 0xe503) is set when the no load condition occurs on the a, b, or c current chan- nel. bit 1 (nload2) in the status1 register is set when the load condition occurs on the d, e, or f current channel. bits[5:0] (noloadx) in the chnoload register (address 0xe608) can be used to determine which channel caused the no load condition. when noloadx is cleared to 0, the channel is not in a no load condition. when noloadx is set to 1, the channel is in a no load condition. no load interrupt the ade7816 includes two interrupts that are associated with the no load feature. the first is associated with the a, b, and c current channels, and it can be enabled by setting bit 0 (nload1) in the mask1 register (address 0xe50b). the second interrupt is associated with the d, e, and f current channels; it can be enabled by setting bit 1 (nload2) in the mask1 register. if the corresponding interrupt is enabled, the no load condition causes the external irq1 pin to go low (see the section). interrupts current signal from hpf or integrator (if enabled) lpf x 2 2 7 ixrmsos[23:0] ixrms[23:0] 10390-016 figure 32. ixrms signal path
ade7816 data sheet rev. 0 | page 24 of 48 energy calibration channel matching the ade7816 provides individual channel gain registers that allow the six current channels and the voltage channel to be matched. matching the channels simplifies the calibration process. the iagain (address 0x4381), ibgain (address 0x4382), icgain (address 0x4383), idgain (address 0x4384), iegain (address 0x4385), and ifgain (address 0x4386) registers adjust the a through f current channels, respectively, whereas the vgain register (address 0x4380) can be used to adjust the voltage channel. the default value of the ixgain registers is 0x00000, which corresp onds to no channel gain. the ixgain can adjust the channel gain by up to 100%. the channel is scaled by ?50% by writing 0xc00000 to the corresponding ixgain register, and it is increased by +50% by writing 0x400000. equation 7 shows the relationship between the ixgain register and the rms measurement. i rms = i rms 0 ? ? ? ? ? ? + 23 2 1 ixgain (7) v rms = v rms 0 ? ? ? ? ? ? + 23 2 1 vgain where i rms 0 and v rms 0 are the current and voltage rms measurements, respectively, without offset correction. changing the content of the ixga in registers affects all calcu- lations based off that channel, including the active and reactive energy. therefore, it is recommended that the channel matching be performed first in the calibration procedure. energy gain calibration the active and reactive energy me asurements can be calibrated on all six channels se parately. this separate calibration allows compensation for meter-to-m eter gain variation. the awgain register (address 0x4391) controls the active power gain calibration on current channel a. the bwgain (address 0x4393), cwgain (address 0x4395), dwgain (address 0x4397), ewgain (address 0x4399), and fwgain (address 0x439b) registers control the active power gain calibra- tion on the b through f current channels, respectively. the default value of the xwgain registers is 0x00000, which corresponds to no gain calibration. the xwgain registers can adjust the active power by up to 100%. the output is scaled by ?50% by writing 0xc00000 to the watt gain registers, and it is increased by +50% by writing 0x400000 to them. equation 8 shows the relationship between the gain adjustment and the xwgain registers. active power = active power 0 ? ? ? ? ? ? + 1 800000x0 xwgain (8) similar gain calibration registers are available for the reactive power. the reactive power on current channel a can be gain calibrated using the avargain (address 0x439d) register. the bvargain (address 0x439f), cvargain (address 0x43a1), dvargain (address 0x43a3), evargain (address 0x43a5), and fvargain (address 0x43a7) registers control the reactive power gain calibration on the b through f current channels, respectively. the xvargain registers affect the reactive power in the same way that the xwgain registers affect the active power. equation 9 shows the relationship between gain adjustment and the xvargain registers. reactive power = reactive power 0 ? ? ? ? ? ? + 1 800000x0 xvargain (9) energy offset calibration the ade7816 includes offset calibration registers for the active and reactive powers on all six channels. offsets can exist in the power calculations due to crosstalk between channels on the pcb and in the ade7816 . the offset calibration allows these offsets to be removed to increase the accuracy of the measure- ment at low input levels. the active power offset can be corrected on current channel a by adjusting the awattos (address 0x4392) register. the bwattos (address 0x4394), cwattos (address 0x4396), dwattos (address 0x4398), ewattos (address 0x439a), and fwattos (address 0x439c) registers control the active power offset calibration on the b through f current channels, respectively. the xwattos registers are 24-bit, signed, twos complement registers with default values of 0. one lsb in the active power offset register is equivalent to 1 lsb in the active power multiplier output. with full-scale current and voltage inputs, the maximum power output is equal to 1ff6a6b = 33,516,139. at ?80 db down from full scale (active power scaled down 10 4 times), one lsb of the xwattos registers represents 0.0298%. equation 10 shows the relationship between the xwattos registers and the active energy reading. xwatthr = xwatthr 0 + (10) ? ? ? ? ? ? )( 8000 sontime accumulati xwattos wthr similar offset calibration registers are available for the reactive power. the reactive power on current channel a can be offset calibrated using the avaros (address 0x439e). the bvaros (address 0x43a0), cvaros (address 0x43a2), dvaros (address 0x43a4), evaros (a ddress 0x43a6), and fvaros (address 0x43a8) registers control the reactive power gain calibration on the b through f current channels, respectively. the xvaros registers affect the reactive powers in the same way that the xwattos registers affect the active power. equation 11 shows the relationship between the xvaros registers and the reactive energy reading. xvarhr = xvarhr 0 + (11) ? ? ? ? ? ? )( 8000 sontime accumulati xvaros varthr
data sheet ade7816 rev. 0 | page 25 of 48 energy phase calibration the ade7816 is designed to function with a variety of current transducers, including those that induce inherent phase errors. a phase error of 0.1 to 0.3 is not uncommon for a current transformer (ct). these phase e rrors can vary from part to part, and they must be correct ed to achieve accurate power readings. the errors associated with phase mismatch are particularly noticeable at low power factors. the ade7816 provides a means of digitally calibrating these small phase errors by introducing a time delay or a time advance. because different sensors can be used on each channel, sepa- rate phase calibration registers are included all six channels. the pcf_a_coeff register (address 0x43b1) can be used to correct phase errors on current channel a. the pcf_b_coeff (address 0x43b2), pcf_c_coeff (address 0x43b3), pcf_d_ coeff (address 0x43b4), pcf_e_coeff (address 0x43b5), and pcf_f_coeff (address 0x43b6) registers control the phase calibration on the b through f current channels, respectively. all registers are 24-bit, unsigned. the ade7816 uses all pass filters to accurately add time advances and delays to the current channels with respect to the voltage channels. a separate filter is included on each of the six current channels. to adjust the time delay or advance, the coefficient of these filters must be adjusted. equation 12, equation 13, and equation 14 show how the coefficients correspond to the phase offset in radians. pcf_x_coeff fraction = )4sin( sin)3sin( ? + ?+ (12) if pcf_x_coeff 0, then pcf_x_coeff = 2 23 pcf_x_coeff fraction (13) if pcf_x_coeff < 0, then pcf_x_coeff = (2 23 + 23 28 ) pcf_x_coeff fraction (14) where is the required current-to-voltage phase adjustment. 8000 )( 2 hzlinefreq = to simplify this calculation, analog devices has a spreadsheet file that calculates this value. to obtain this spreadsheet, contact a representative of analog devices. by default, the pcf_x_coeff registers are set to 0. this setting does not, however, result in a 0 phase shift. on startup, the pcf_x_coeff registers should be set to 0x400c4a for a 50 hz system and 0x401235 for a 60 hz system. rms offset calibration the ade7816 includes an rms offset compensation register for each channel, as follows: iarmsos (address 0x438b), ibrmsos (address 0x438c), icrmsos (address 0x438d), idrmsos (address 0x438e), iermsos (address 0x438f), ifrmsos (address 0x4390), and vrmsos (a ddress 0x438a). these 24-bit, signed registers are used to remove offsets in the current and voltage rms calculations. the rms offset compensation register is added to the squared current and voltage signal before the square root is executed. equation 15 shows the relationship between the rms measurement and the offset adjustment. ixrmsos ii rms rms += 128 2 0 (15) vrmsos vv rms rms += 128 2 0 where i rms 0 and v rms 0 are the current and voltage rms measurement, respectively, without offset correction.
ade7816 data sheet rev. 0 | page 26 of 48 power quality features this section describes the power quality features that are available in the ade7816 . selecting a current channel group when using the power quality features on the current channels, the group of channels to be monitored must be selected. bit 14 (channel_sel) of the compmode register (address 0xe60e) can be used to make this selection. to select the a, b, and c current channels for the current channel power quality measurements, channel_sel must be set to 0 (default). to select the d, e, and f current channels for the current channel power quality measurements, channel_sel must be set to 1. if all channels require monitoring, the monitoring must be done in series by modifying the channel_sel bit after data is obtained. the settling time of each power quality measurement is provided in the section that pertains to each power quality feature. instantaneous waveforms the ade7816 provides access to the current and voltage channel waveform data. this information allows the instantaneous data to be analyzed in more detail, including reconstruction of the current and voltage input for harmonic analyses. these measure- ments are available from a set of 24-bit, signed registers. the voltage channel has a dedicated register, vwv (address 0xe510), whereas the current channels share three registers: iawv/idwv (address 0xe50c), ibwv/iewv (address 0xe50d), and icwv/ ifwv (address 0xe50e). a group of current channels (a, b, c or d, e, f) must be selected by bit 14 (channel_sel) of the compmode register (see the selecting a current channel group section). all measurements are updated at a rate of 8 khz. the ade7816 provides an interrupt status bit, dready (bit 17 of the status0 register, address 0xe502), that is triggered at a rate of 8 khz, allowing measurements to be synchronized with the instanta- neous update signal rate. the instantaneous update signal can also be configured to trigger an interrupt on the external pin by setting the dready bit (bit 17) in the mask0 register (address 0xe50a). with the specified full-scale analog input signal of 0.5 v, the expected reading on the current and voltage waveform register is approximately 5,989,256 (dec). the instantaneous waveforms have no additional settling time, and, therefore, if the channel_s el bit is modified to change the group of current channels being measured, the new result is available in 125 s (8 khz). zero-crossing detection zero-crossing detection the ade7816 has a zero-crossing (zx) detection circuit on the voltage and current channels. zero-crossing detection allows measurements to be synchroniz ed to the frequency of the incoming waveforms. the zero-crossing events are filter ed internally by an lpf. the lpf is intended to eliminate all harmonics of 50 hz and 60 hz systems, and to help identify the zero-crossing events on the fundamental components of both current and voltage channels. the digital filter has a pole at 80 hz and is clocked at 256 khz. as a result, there is a phase lag between the analog input signal and the output of the lpf. the error in zx detection is 0.0703 for 50 hz systems and 0.0843 for 60 hz systems. the phase lag response of the lpf results in a time delay of approximately 31.4 or 1.74 ms (at 50 hz) between its input and output. the overall delay between the zero crossing on the analog inputs and the zx detection that is obtained after lpf1 is about 39.6 or 2.2 ms (at 50 hz). figure 33 shows how the zero-crossing signal is detected. to provide further protection from noise, input signals to the voltage channel with an amplitude of <10% of full scale do not generate zero-crossing events at all. the zx detection circuit of the current channels is active for all input signals, independent of their amplitudes. ixgain or vgain reference hpf pga adc ia, ib, ic, id, ie, if, or v zx detection lpf_zx ia, ib, ic, id, ie, if, or v 39.6 or 2.2ms @ 50hz 1 0.855 0v zx zx zx zx lpf_zx output 10390-017 figure 33. zero-crossing detection
data sheet ade7816 rev. 0 | page 27 of 48 the ade7816 contains four zero-crossing detection circuits, one dedicated for the voltage channel and three for the current channels. a group of current channe ls (a, b, c or d, e, f) must be selected by bit 14 (channel_sel) of the compmode register, address 0xe60e (see the selecting a current channel group section). when switching between channel groups, a set- tling time of 10 ms (50 hz) or 8 ms (60 hz) is required. each circuit drives one flag in the st atus1 register (address 0xe503). for example, if a zero crossing occurs on the voltage channel, bit 9 (zxv) in the status1 register goes high. if a zero-crossing event occurs on current channel a and the channel_sel bit in the compmode register is set to 0, bit 12 (zxi1) in the status1 register is set to 1. zero-crossing timeout each zero-crossing detection circuit has an associated timeout register. this register is loaded with the value that is written into the 16-bit zxtout register (address 0xe60d) and is decremented by 1 lsb every 62.5 s (16 khz clock). the register is reset to the zxtout value every time a zero crossing is detected. the default value of this register is 0xffff. if the timeout register decrements to 0 before a zero crossing is detected, the corresponding status1 bit is set. there is a zero-crossing timeout circuit that is dedicated to the voltage channel. for example, if a zero-crossing timeout event occurs on the voltage channel, bit 3 (zxtov) in the status1 register is set. there are three zero-crossing timeout circuits for the six current channels. a group of current channels, a, b, c or d, e, f, must be selected by the channel_sel bit of the compmode register (see the selecting a current channel group section). for example, if a zero-crossing timeout event occurs on current channel d and the channel_sel bit in the compmode register is set to 1, bit 6 (zxtoi1) in the status1 register is set to 1. the resolution of the zxtout regi ster is 62.5 s (16 khz clock) per lsb. therefore, the maximum timeout period for an interrupt is 4.096 sec (2 16 /16 khz). peak detection the ade7816 includes an instantaneous peak detection feature that stores the maximum absolute value reached on the current and voltage channels over a fixed number of half line cycles. the peakcyc register (address 0x e703) stores the number of half line cycles used for all peak measurements. the peak detection feature is av ailable on the voltage channel and three of the current channels. a group of current channels (a, b, c or d, e, f) must be selected by the channel_sel bit of the compmode register (see the selecting a current channel group section). when switching between current channel groups, no additional settling time is required. however, the peakcyc register should be rewritten to reset the measurement. by default, all three current channels are included in the peak detection measurement. if only one or two current channels are required, bits[4:2] (peakselx) of the mmode register (address 0xe700) can be set to 0 to disable a channel. note that one peakselx bit must always be set to 1 to enable the feature. the results of the current and voltage peak detection are stored in the lowest 24 bits of two 32- bit, unsigned registers, ipeak (address 0xe500) and vpeak (address 0xe501). the peak detection measurements are update d at the end of the peak cycle specified in the peakcyc register. at that time, bit 24 (pkv) and bit 23 (pki) in the status1 register go high, signaling a peak event. to determine which current channel caused the peak event, bits[26:24] (ipchannelx) in the ipeak register must be read. setting the peakcyc register the 8-bit, unsigned peakcyc register contains the program- mable peak detection period. the peak detection period is the number of half line cycles over which the peak measurement is measured. each lsb of the peakcyc register corresponds to one half line cycle period. the peakcyc register holds a maximum value of 255. at 50 hz, the maximum peak cycle time is 2.55 seconds. ? ? ? ? ? ? 2 50 1 255 = 2.55 sec at 60 hz, the maximum peak cycle time is 2.125 seconds. ? ? ? ? ? ? 2 60 1 255 = 2.125 sec overcurrent and overvoltage detection the ade7816 provides an overcurrent and overvoltage feature that detects whether the absolute value of the current or voltage waveform exceeds a programmable threshold. this feature uses the instantaneous voltage and current signals. the two registers used to set the voltage and current channel threshold are ovlvl (address 0xe508) and oilvl (address 0xe507), respectively. the oilvl threshold register determines the threshold for all current channels. the default value of the ovlvl and oilvl registers is 0xffffff, which effectively disables the feature. figure 34 shows the operation of the overvoltage detection feature. ovlvl bit 18 (ov) of status1 voltage channel overvoltage detected status1[18] cancelled by a write of status1 with ov bit set. 10390-018 figure 34. overvoltage detection
ade7816 data sheet rev. 0 | page 28 of 48 as shown in figure 34, the ov bit (bit 18) in the status1 register (address 0xe503) is set to 1 if the ade7816 detects an overvoltage condition. the overcurrent detection feature works in a similar manner; however, a group of current channels (a, b, c or d, e, f) must be selected by bit 14 (channel_sel) of the compmode register, address 0xe60e (see the selecting a current channel group section). when switching between current channel groups, no additional settling time is required and the feature continues to monitor at an 8 khz rate. if an overcurrent condition is detected on any of the selected current channels, the oi bit (bit 17) of the status1 register is set to 1. to determine the current channel(s) causing the overcurrent event, the oichannelx bits (bit 3, bit 4, and bit 5) of the chstatus register are used. setting the ovlvl and oilvl registers the content of the overvoltage (ovlvl) and overcurrent (oilvl), 24-bit, unsigned registers is compared to the absolute value of the voltage and current channels. the maximum value of these registers is 5,928,256 (0x5a7540) with full scale inputs. when either the ovlvl or oilvl register is equal to this value, the overvoltage or overcurrent conditions are never detected. writing 0x0 to these registers si gnifies that the overvoltage or overcurrent conditions are continuously detected, and the corresponding interrupts are permanently triggered. overvoltage and overcurrent interrupts two interrupts are associated with the overvoltage and overcurrent features. the first interrupt is associated with the overvoltage feature; it is enabled by setting the ov bit (bit 18) of the mask1 register (address 0xe50b). when this bit is set, an overvoltage condition causes the external irq1 pin to be pulled low. a second interrupt is associated with the overcurrent detection feature. this interrupt is enabled by setting the oi bit (bit 17) of the mask1 register. when this bit is set, an overcurrent condition on any of the selected current channels causes the external irq1 pin to be pulled low. indication of power direction the ade7816 includes sign indication on the active and reactive power measurements. sign indication allows positive and negative energy to be identified and billed separately, if required. it also helps detect a miswiring condition. this feature is available on three channels at a time. a group of current channels (a, b, c or d, e, f) must be selected by bit 14 (channel_sel) of the compmode register at address 0xe60e (see the selecting a current channel group section). the three-sign indication bits that indicate the polarity of the active power are bit 0 (w1sign), bit 1 (w2sign), and bit 2 (w3sign) of the chsign register (address 0xe617). w1sign indicates the direction of power on the a or d current channel, w2sign indicates the direction of power on the b or e current channel, and w3sign indicates the direction of power on the c or f current channel. an additional three bits, var1sign (bit 4), var2sign (bit 5), and var3sign (bit 6), also in the chsign register, provide the direction of the reactive power. all of these bits are unlatched and read only. a low reading (0) on any of these bits indicates that the corresponding power reading is positive; a high reading (1) indicates that the corresponding power reading is negative. in addition to the sign indication bits, the ade7816 also includes reverse power status bits and associ ated interrupts. the status bits are located in the status0 register (address 0xe502). the reverse power bits are set to 1 when the sign of the power changes. bit 6 (revap1) monitors the a or d current channel, bit 7 (revap2) monitors the b or e channel, and bit 8 (revap3) monitors the c or f current channel. similarly, bit 10 (revrp1), bit 11 (revrp2), and bit 12 (revrp3) monitor the reactive power. both positive-to-negative and negative-to-positive changes result in the corresponding status bit being set. each status bit has a cor- responding interrupt enable bit that is located in the mask0 register (address 0xe50a). if the corresponding mask0 bit is set, a change in active energy power direction causes the external irq0 pin to be pulled low (see the interrupts section for more details). angle measurements the ade7816 can measure the time delay between the current and voltage inputs. it can also be configured to measure the time between the six current channels. the negative-to-positive transitions identified by the zero-crossing detection circuit are used as a start and stop for the measurement (see figure 35). current channel x angle voltage 10390-019 figure 35. voltage-to-current time delay there are three angle registers that store the results of the time delay. a group of current channels (a, b, c or d, e, f) must be selected by bit 14 (channel_sel) of the compmode register (see the selecting a current channel group section). when bits[10:9] (anglesel) of the compmode register are set to 00b (default), the time delays between the current channels and the voltage channel are measured. the angle0 register (address 0xe601) stores the delay between the voltage and the a or d current channel. the angle1 register (address 0xe602) stores the delay between the voltage and the b or e current channel. the angle2 register (address 0xe603) stores the delay between the voltage and the c or f current channel. the time delay between the current and voltage inputs can be used to characterize how balanced the load is. the delays between phase voltages and currents can be used to compute the power factor, as shown in equation 16. ? ? ? ? ? ? ? ? ? ? ? khz256 360 coscos line o x f anglex ? (16) where f line is 50 hz or 60 hz.
data sheet ade7816 rev. 0 | page 29 of 48 this method of determining the power factor does not take into account the effect of any harmonics. when bits[10:9] (anglesel) of the compmode register are set to 10b, the time delays (ang les) between curre nt channels are measured. table 10 shows the current channel-to-channel delay measure-ments that are available. table 10. available channel- to-channel measurements (anglesel = 10b) channel-to-channel measurements channel_sel (compmode[14]) angle0 angle1 angle2 0 a to b a to c b to c 1 a to e d to f e to f the angle0 (address 0xe601), angle1 (address 0xe602), and angle2 (address 0xe603) registers are 16-bit, unsigned registers with 1 lsb corresponding to 3.90625 s (256 khz clock), which corresponds to a resolution of 0.0703 (360 50 hz/256 khz) for 50 hz systems and 0.0843 (360 60 hz/256 khz) for 60 hz systems. period measurement the ade7816 provides the period measurement of the line in the voltage channel. the period register (address 0xe607) is a 16-bit, unsigned register that updates every line period. due to internal filtering, a settling time of 30 ms to 40 ms is associ- ated with this measurement. the period measurement has a resolution of 3.90625 s/lsb (256 khz clock), which represents 0.0195% (50 hz/256 khz) when the line frequency is 50 hz and 0.0234% (60 hz/256 khz) when the line frequency is 60 hz. the value of the period register for 50 hz networks is approximately 5120 (256 khz/50 hz) and for 60 hz networks is approximately 4267 (256 khz/60 hz). the length of the register enables the measurement of line frequencies that are as low as 3.9 hz (256 khz/2 16 ). the period register is stable at 1 lsb when the line is established, and the measurement does not change. the following expressions can be used to compute the line period and frequency, using the period register: [] (17) sec 3e256x0 1 + = 0] period[15: t l ]hz[ 1 3e256x0 + = 0] period[15: f l voltage sag detection the ade7816 includes a sag detection feature that warns the user when the absolute value of the line voltage falls below the programmable threshold for a programmable number of line cycles. this feature can provide an early warning signal that the line voltage is dropping out. the voltage sag feature is controlled by two registers: sagcyc (address 0xe704) and saglvl (address 0xe509). these register s control the sag period and the sag voltage threshold, respectively. sag detection is disabled by defa ult and can be enabled by writing a nonzero value to both the sagcyc and saglvl registers. if either register is set to 0, the sag feature is disabled. if a voltage sag condition occurs, the sag bit (b it 16) in the status1 register (address 0xe503) is set to 1. setting the sagcyc register the 8-bit, unsigned sagcyc regi ster contains the programmable sag period. the sag period is the number of half line cycles below which the voltage channel must remain before a sag condition occurs. each lsb of the sagcyc register corresponds to a half line cycle period. the sagcyc register holds a maximum value of 255. at 50 hz, the maximum sag cycle time is 2.55 seconds. ? ? ? ? ? ? 2 50 1 255 = 2.55 sec at 60 hz, the maximum sag cycle time is 2.125 seconds. ? ? ? ? ? ? 2 60 1 255 = 2.125 sec if the sagcyc value is modified after the feature is enabled, the new sagcyc period is effective immediately. therefore, it is possible for a sag event to be caused by a combination of sag cycle periods. to prevent any overlap, the saglvl register should be reset to 0 to effectively disable the feature before the new cycle value is written to the sagcyc register. setting the saglvl register the content of the 24-bit saglvl register is compared to the absolute value of the output from the hpf. writing 5,928,256 (0x5a7540) to the saglvl register sets the sag detection level at full scale. this results in the sag event triggering continuously. writing 0x00 or 0x01 puts the sag detection level at 0; therefore, the sag event is never triggered. voltage sag interrupt the ade7816 includes an interrupt that is associated with the voltage sag detection feature. if this interrupt is enabled, a voltage sag event causes the external irq1 pin to go low. this interrupt is disabled by default and can be enabled by setting the sag bit (bit 16) in the mask1 register, address 0xe50b (see the section). interrupts
ade7816 data sheet rev. 0 | page 30 of 48 checksum g i , where i = 0, 1, 2, , 31 is the coefficient of the generating polynomial defined by the ieee802.3 standard as follows: the ade7816 has a 32-bit checksum register (address 0xe51f) that ensures that certain important configuration registers maintain their desired value during normal operation. g ( x ) = x 32 + x 26 + x 23 + x 22 + x 16 + x 12 + x 11 + x 10 + (18) x 8 + x 7 + x 5 + x 4 + x 2 + x + 1 g 0 = g 1 = g 2 = g 4 = g 5 = g 7 = 1 (19) g 8 = g 10 = g 11 = g 12 = g 16 = g 22 = g 26 = g 31 = 1 the registers that are included in this feature are mask0, mask1, compmode, gain, config, mmode, accmode, lcycmode, hsdc_cfg, plus four additional 16-bit reserved registers and six 8-bit reserved internal registers. all reserved registers always have default values. the ade7816 computes the cyclic redundancy check (crc) based on the ieee802.3 standard. the registers are introduced, one by one, into a linear feedback shift register (lfsr) based generator, starting with the least significant bit (as shown in figure 36 ). the 32-bit result is written in the checksum register. after power-up or a hardware/software reset, the crc is computed on the default values of the registers. the default value of the checksum register is 0x33666787. all of the other g i coefficients are equal to 0. fb ( j) = a j ? 1 xor b 31 ( j ? 1) (20) b 0 ( j) = fb ( j) and g 0 (21) b i (j) = fb ( j) and g i xor b i ? 1 ( j ? 1), i = 1, 2, 3, ..., 31 (22) equation 20, equation 21, and equation 22 must be repeated for j = 1, 2, , 256. the value written into the checksum register con- tains bit b i (256) , i = 0, 1, , 31. after the bits from the reserved internal register pass through the lfsr, the value of the crc (which is obtained at step j = 48) is 0x33660787. figure 37 shows how the lfsr works. the mask0, mask1, compmode, gain, config, mmode, accmode, lcycmode, and hsdc_cfg registers, along with the four 16-bit reserved registers and six 8-bit reserved internal registers, form the bits[a 255 , a 254 , , a 0 ] used by the lfsr. bit a 0 is the least significant bit of the first internal register to enter the lfsr; bit a 255 is the most significant bit of the mask0 register, the last register to enter the lfsr. the formulas that govern the lfsr are as follows: two different approaches can be followed in using the checksum register. one is to compute the crc, based on equation 18 to equation 22, and then compare the value against the checksum register. another is to periodically read the checksum register. if two consecutive readings differ, it can be assumed that one of the registers has changed value and that, therefore, the ade7816 configuration has changed. the recommended response is to initiate a hardware/software reset that sets the values of all registers (including the reserved ones) to the default, and then reinitialize the configuration registers. b i (0) = 1, where i = 0, 1, 2, , 31, the initial state of the bits that form the crc. bit b 0 is the least significant bit, and bit b 31 is the most significant bit. 31 0 0 15 0 15 0 0 15 31 255 248 240 232 224 216 7070707 0 0 07 07 40 32 24 16 8 7 mask0 mask1 compmode reserved gain internal register internal register internal register internal register internal register internal register lfsr generator 10390-020 figure 36. checksum register calculation b 0 lfsr fb g 0 g 1 g 2 g 31 b 1 g 3 b 2 b 31 a 255 , a 254 ,...., a 2 , a 1 , a 0 10390-021 figure 37. lfsr generator used in checksum register calculation
data sheet ade7816 rev. 0 | page 31 of 48 outputs this section describes the outputs from the ade7816 . interrupts the ade7816 has two interrupt pins, irq0 and irq1 . each pin is managed by a 32-bit interrupt mask register, mask0 and mask1 (address 0xe50a and address 0xe50b), respectively. to enable an interrupt, a bit in the maskx register must be set to 1. to disable an interrupt, the bit must be cleared to 0. two 32-bit status registers, status0 and status1 (address 0xe502 and address 0xe503, respectively), are associated with the interrupts. when an interrupt event occurs in the , the corre- sponding flag in the interrupt status register is set to a logic 1 (see and ). if the mask bit for this interrupt in the interrupt mask register is logic 1, the ade7816 table 30 table 31 irqx logic output goes active low. the flag bits in the interrupt status register are set, irrespective of the state of the mask bits. to determine the source of the interrupt, the microcontroller must perform a read of the corresponding statusx register and identify which bit is set to 1. to erase the flag in the status register, write back to the statusx register with the flag set to 1. after an interrupt pin goes low, the status register is read and the source of the interrupt is identified. then, the status register is written back, with no changes, to clear the status flag to 0. the irqx pin remains low until the status flag is cancelled. by default, all interrupts are disabled, with the exception of the rstdone interrupt. this interrupt can never be masked (disabled) and, therefore, bit 15 (rstdone) in the mask1 register does not have any functionality. the irq1 pin always goes low, and bit 15 (rstdone) in the status1 register is set to 1 whenever a power-up or a hardware/software reset process ends. to cancel the rstdone status flag, the status1 register nust be written with bit 15 (rstdone) set to 1. communication serial interface selection after reset, the hsdc port is always disabled. choose between the i 2 c and spi ports by manipulating the ss /hsa pin after power-up or after a hardware reset. if the ss /hsa pin is held high, the uses the i 2 c port until a new hardware reset is executed. if the ade7816 ss /hsa pin is toggled high to low three times after power-up or after a hardware reset, the uses the spi port until a new hardware reset is executed. this manipulation of the ade7816 ss /hsa pin can be accomplished in two ways. the first option is to use the ss /hsa pin of the master device (that is, the microcontroller) as a regular i/o pin and toggle it three times. the second option is to execute three spi write operations to a location in the address space that is not allocated to a specific register (such as address 0xebff, where 8-bit writes can be executed). ade7816 these writes allow the ss /hsa pin to toggle three times. see the spi write operation section for details on the write protocol that is involved. after the serial port choice is completed, it must be locked. if i 2 c is the active serial port, bit 1 (i2c_lock) of the config2 register (address 0xec01) must be set to 1 to lock it in. from then on, the ade7816 ignores spurious toggling of the ss /hsa pin, and an eventual switch to use of the spi port is no longer possible. if the spi is the active serial port, any write to the config2 register locks the port. from then on, a switch to the i 2 c port is no longer possible. the functionality of the ade7816 is accessible via several on-chip registers. the contents of these registers can be updated or read, using either the i 2 c or spi interfaces. the hsdc port provides the instantaneous values of the voltages and current channels. i 2 c-compatible interface the ade7816 supports a fully licensed i 2 c interface. the i 2 c interface is implemented as a full hardware slave. sda is the data i/o pin, and scl is the serial clock. these two pins are shared with the mosi and sclk pins, respectively, of the on-chip spi interface. the maximum serial clock frequency supported by this interface is 400 khz. the sda and scl pins are used for data transfer and are con- figured in a wire-anded format that allows arbitration in a multimaster system. the transfer sequence of an i 2 c system consists of a master device initiating a transfer by generating a start condition while the bus is idle. the master transmits the address of the slave device and the direction of the data transfer in the initial address transfer. if the slave acknowledges, the data transfer is initiated. this continues until the master issues a stop condition and the bus becomes idle. i 2 c write operation the write operation, using the i 2 c interface of the ade7816 , initiated when the master generates a start condition, consists of one byte representing the address of the ade7816 , followed by the 16-bit address of the target register and by the value of the register. the most significant seven bits of the address byte constitute the address of the ade7816 , which is 0111000b. bit 0 of the address byte is a read/ write bit. because this is a write operation, it must be cleared to 0; therefore, the first byte of the write operation is 0x70. after every byte is received, the generates an acknowledge. the register can be 8, 16, or 32 bits in length. after the last bit of the register is transmitted and the acknowledges the transfer, the master generates a stop condition. the addresses and the register content are sent with the most significant bit first. see for details of the i 2 c write operation. ade7816 ade7816 figure 39
ade7816 data sheet rev. 0 | page 32 of 48 i 2 c read operation the read operation, using the i 2 c interface of the ade7816 , is accomplished in two stages. the first stage sets the pointer to the address of the register; the second stage reads the contents of the register (see figure 40 ). the first stage is initiated when the master generates a start con- dition. it consists of one byte, representing the address of the ade7816 , followed by the 16-bit address of the target register. the ade7816 acknowledges every byte received. the address byte is similar to the address byte of a write operation and is equal to 0x70 (see the i 2 c write operation section for details). after the last byte of the register address is sent and acknowledged by the ade7816 , the second stage begins with the master generating a new start condition, followed by an address byte. the most significant seven bits of this address byte constitute the address of the ade7816 , which is 0111000b. bit 0 of the address byte is a read/ write bit. because this is a read operation, it must be set to 1; therefore, the first byte of the read operation is 0x71. after this byte is received, the generates an acknowledge. then the sends the value of the register, and, after every eight bits are received, the master generates an acknowledge. all the bytes are sent with the most significant bit first. registers can be 8, 16, or 32 bits. after the last bit of the register is received, the master does not acknowledge the transfer but, instead, generates a stop condition. ade7816 ade7816 spi-compatible interface the ade7816 spi is always a slave of the communication and consists of four pins (with dual functions): sclk/scl, mosi/sda, miso/hsd, and ss /hsa. the functions used in the spi-compatible interface are sclk, mosi, miso, and ss . the serial clock for a data transfer is applied at the sclk logic input. this logic input has a schmitt trigger input structure that allows the use of slow rising (and falling) clock edges. all data transfer operations synchronize to the serial clock. data shifts into the at the mosi logic input on the falling edge of sclk, and the samples it on the rising edge of sclk. data shifts out of the at the miso logic output on a falling edge of sclk and can be sampled by the master device on the raising edge of sclk. the most significant bit of the word is shifted in and out first. the maximum serial clock frequency that is supported by this interface is 2.5 mhz. miso stays in high impedance when no data is transmitted from the . shows details of the connection between the spi and a master device containing a spi interface. ade7816 ade7816 ade7816 ade7816 figure 38 ade7816 mosi/sda miso/hsd sclk/scl ade7816 mosi miso sck spi device ss/hsa ss 10390-024 figure 38. connecting the ade7816 spi with a spi device acknowledge generated by ade7816 start stop s a c k a c k a c k a c k a c k a c k a c k s 0 15 slave address ms 8 bits of register address ls 8 bits of register address byte 3 (ms) of register byte 2 of register byte 1 of register byte 0 (ls) of register 87 031 1615 87 0 0 7 1110000 10390-022 figure 39. i 2 c write operation of a 32-bit register acknowledge generated by ade7816 acknowledge generated by master start s a c k a c k a c k 0 15 slave address msb 8 bits of register address lsb 8 bits of register address 87 0 1110000 start stop s a c k a c k a c k a c k s 0 slave address byte 3 (msb) of register byte 2 of register byte 1 of register byte 0 (lsb) of register 31 16 15 8 7 0 0 7 1110001 acknowledge generated by ade7816 n o a c k 10390-023 figure 40. i 2 c read operation of a 32-bit register
data sheet ade7816 rev. 0 | page 33 of 48 the ss logic input is the chip select input. this input is used when multiple devices share the serial bus. drive the ss input low for the entire data transfer operation. bringing ss high during a data transfer operation aborts the transfer and places the serial bus in a high impedance state. a new transfer can then be initiated by returning the ss logic input to low. however, because aborting a data transfer before completion leaves the accessed register in a state that cannot be guaranteed, the value of a register should be verified by reading it back each time it is written. the protocol is similar to the protocol used with the i 2 c interface. spi read operation the read operation, using the spi interface, initiates when the master sets the ss /hsa pin low and begins sending one byte, representing the address of the , on the mosi line. the master sets data on the mosi line starting with the first high-to- low transition of sclk. the spi samples data on the low-to-high transitions of sclk. the most significant seven bits of the address byte can have any value, but, as good programming practice, they should be different from 0111000b, the seven bits used in the i 2 c protocol. bit 0 (read/ ade7816 ade7816 write ) of the address byte must be set to 1 for a read operation. next, the master sends the 16-bit address of the register to be read. after the receives the last address bit of the register on a low-to-high transition of sclk, it begins to transmit its contents on the miso line when the next sclk high-to-low transition occurs; thus, the master can sample the data on a low-to-high sclk transition. after the master receives the last bit, it sets the ade7816 ss and sclk lines high, and the communication ends. the data lines, mosi and miso, go into a high impedance state (see ). figure 41 spi write operation the write operation, using the spi interface, initiates when the master sets the ss /hsa pin low and begins sending one byte, representing the address of the , on the mosi line. the master sets data on the mosi line, starting with the first high-to- low transition of sclk. the spi samples data on the low-to-high transitions of sclk. the most significant seven bits of the address byte can have any value, but, as a good programming practice, they should be different from 0111000b, the seven bits that are used in the i 2 c protocol. bit 0 (read/ ade7816 write ) of the address byte must be 0 for a write operation. next, the master sends the 16-bit address of the register that is written and the 32-, 16-, or 8-bit value of that register without losing any sclk cycle. after the last bit is trans- mitted, the master sets the ss and sclk lines high at the end of the sclk cycle and the communication ends. the data lines, mosi and miso, go into a high impedance state (see ). figure 42 1 0 15 14 sclk mosi miso 10 31 30 1 0 0 00000 register value register address ss 10390-025 figure 41. spi read operation of a 32-bit register 0 15 14 sclk mosi 103130 10 0 0 0 0000 register address register value ss 10390-026 figure 42. spi write operation of a 32-bit register
ade7816 data sheet rev. 0 | page 34 of 48 hsdc interface the high speed data capture (hsdc) interface is disabled by default. it can be used only if the ade7816 is configured with an i 2 c interface. the ade7816 spi interface cannot be used simultaneously with the hsdc port. bit 6 (hsdcen) in the config register (address 0xe618) activates hsdc when set to 1. if the hsdcen bit is cleared to 0, the default value, the hsdc interface is disabled. setting the hsdcen bit to 1 when the spi is in use does not have any effect. the hsdc port is an interface for sending up to four 32-bit words to an external device (usually a microprocessor or a dsp). the words represent the instantaneous values of the currents and voltage. the registers that are transmitted are iawv/idwv, i b w v / i e w v, i c w v / i f w v, a n d v w v. a l l a r e 2 4 - b i t r e g i s t e r s that are sign extended to 32 bits. the hsdc port can be interfaced with the spi or similar interfaces. hsdc is always a master of the communication and consists of three pins: hsa, hsd, and hsclk. hsa represents the select signal. it stays active low or high when a word is transmitted, and it is usually connected to the select pin of the slave. hsd sends data to the slave, and it is usually connected to the data input pin of the slave. hsclk is the serial clock line that is generated by the ade7816 , and it is usually connected to the serial clock input of the slave. figure 43 shows the connections between the ade7816 hsdc and slave devices containing a spi interface. miso/hsd hsclk ade7816 miso sck spi device ss/hsa ss 10390-027 figure 43. connecting the ade7816 hsdc with a spi the hsdc communication is managed by the hsdc_cfg register, address 0xe706 (see table 28 ). it is recommended that the hsdc_cfg register be set to the desired value before enabling the port, using bit 6 (hsdcen) in the config register. in this way, the state of various pins belonging to the hsdc port do not take levels that are inconsistent with the desired hsdc behavior. after a hardware reset or power-up, the miso/hsd and ss /hsa pins are set high. bit 0 (hclk) in the hsdc_cfg register determines the serial clock frequency of the hsdc communication. when hclk is 0 (the default value), the clock frequency is 8 mhz. when hclk is 1, the clock frequency is 4 mhz. a bit of data is transmitted for every hsclk high-to-low transition. the slave device that receives data from hsdc samples the hsd line on the low-to-high transition of hsclk. the words can be transmitted as 32-bit or 8-bit packages. when bit 1 (hsize) in the hsdc_cfg register is 0 (the default value), the words are transmitted as 32-bit packages. when bit hsize is 1, the registers are transmitted as 8-bit packages. the hsdc interface transmits the words msb first. when bit 2 (hgap) is set to 1, a gap of seven hsclk cycles is introduced between packages. when the hgap bit is cleared to 0 (the default value), no gap is introduced between packages and the communication time is shortest. in this case, hsize does not have any influence on the communication, and a data bit is placed on the hsd line with every hsclk high-to-low transition. for correct operation, bits[4:3] (hxfer[1:0]) must be set to a value of 01b. the words representing the instantaneous values of currents and voltage are transmitted in the following order: i aw v / i d w v, v w v, i b w v / i e w v, v w v, i c v w / i f w v, a n d vwv, followed by one 32-bit word of all 0s. note that the voltage waveform is sent three times. bit 14 (channel_sel) of the compmode register (address 0xe60e) can be used to select which group of current channels is transmitted (see the selecting a current channel group section). bit 5 (hsapol) of the hsdc_cfg register determines the hsa function polarity of the ss /hsa pin during communication. when the hsapol bit is 0 (the default value), hsa is active low during the communication. this means that hsa stays high when no communication is in progress. when the communication starts, hsa goes low and stays low until the communication ends. then it goes back to high. when hsapol is 1, the hsa function of the ss /hsa pin is active high during the communication. this means that hsa stays low when no communication is in progress. when the communication starts, hsa goes high and stays high until the communication ends; then it goes back to low. bits[7:6] of the hsdc_cfg register are reserved. any value written into these bits has no consequence on hsdc behavior. figure 44 shows the hsdc transfer protocol for hgap = 0, hxfer[1:0] = 01, and hsapol = 0. note that the hsdc interface sets a data bit on the hsd line every hsclk high- to-low transition, and the value of bit hsize is irrelevant. figure 45 shows the hsdc transfer protocol for hsize = 0, hgap = 1, hxfer[1:0] = 01, and hsapol = 0. note that the hsdc interface introduces a gap of seven hsclk cycles between every 32-bit word. figure 46 shows the hsdc transfer protocol for hsize = 1, hgap = 1, hxfer[1:0] = 01, and hsapol = 0. note that the hsdc interface introduces a gap of seven hsclk cycles between every 8-bit word. see table 28 for the hsdc_cfg register and descriptions for the hclk, hsize, hgap, hxfer[1:0], and hsapol bits.
data sheet ade7816 rev. 0 | page 35 of 48 table 11 lists the time that is required to execute an hsdc data transfer for all hsdc_cfg register settings. table 11. communication times for various hsdc settings hxfer[1:0] hgap hsize 1 hclk communication time (s) 01 0 n/a 0 28 01 0 n/a 1 56 01 1 0 0 33.25 01 1 0 1 66.5 01 1 1 0 51.625 01 1 1 1 103.25 1 n/a means not applicable. hsclk hsd hsa 0 31 0 31 0 31 0 31 iawv/idwv (32) vwv (32) ibwv/iewv (32) 0000000 (32) 10390-028 figure 44. hsdc communication for hgap = 0, hxfer[1:0] = 01, and hsapol = 0; hsize is irrelevant hsclk hsd hsa 0 31 0 31 0 31 iawv/idwv (32) 7 hsclk cycles vwv (32) ibwv/iewv (32) 7 hsclk cycles 0 31 00000000 (32) 10390-029 figure 45. hsdc communication for hsize = 0, hgap = 1, hxfer[1:0] = 01, and hsapol = 0 hsclk hsd hsa 24 31 16 23 8 15 0 7 iawv/idwv (byte 3) 7 hsclk cycles iawv/idwv (byte 2) iawv/idwv (byte 1) 00 (byte 0) 7 hsclk cycles 10390-030 figure 46. hsdc communication for hsize = 1, hgap = 1, hxfer[1:0] = 01, and hsapol = 0
ade7816 data sheet rev. 0 | page 36 of 48 registers register protection to protect the integrity of the data stored in the data memory (located at address 0x4380 to address 0x43be), a write protection mechanism is available. by default, the protection is disabled, and registers that are located between address 0x4380 and address 0x43be can be written without restriction. when the protection is enabled, no writes to these registers are allowed. registers can always be read, without restriction, independent of the write protection state. to enable the protection, write 0xad to an internal 8-bit register that is located at address 0xe7fe, followed by a write of 0x80 to an internal 8-bit register located at address 0xe7e3. it is recommended that the write protection be enabled before starting the dsp. if any register requires changing after this time, disable the protection, change the value, and then reenable the protection. there is no need to stop the dsp to change these registers. to disable the protection, write 0xad to an internal 8-bit register that is located at address 0xe7fe, followed by a write of 0x00 to an internal 8-bit register that is located at address 0xe7e3. register format the ade7816 includes 8-, 16-, and 32-bit, signed and unsigned registers. all signed registers are in twos complement format. some of the internal measurements are 24 bits long and have been extended to 32 bits prior to communication. this extension is accomplished in three different ways: sign extending (se), zero padding (zp), or zero padded and sign extended (zpse). when sign extending is used, the sign bit (bit 23) of the twos complement signed number is duplicated in the uppermost byte prior to communication. zero padding is achieved by writing 0s into the upper most byte prior to transmission. this format is used for unsigned numbers only. zero padded and sign extended formats are shown in figure 47 and involve padding the most significant bits with 0s and sign extending bits[27:24]. 31 28 27 24 23 0 24-bit number 0000 bits[27:24] are equal to bit 23 bit 23 is a sign bit 10390-031 figure 47. zpse co mmunication format the communication format of each register is specified in the register maps section (see table 12 through table 15 ).
data sheet ade7816 rev. 0 | page 37 of 48 register maps table 12. calibration and power quality registers address register name r/w 1 bit length bit length during communication 2 type 3 default value description 0x4380 vgain r/w 24 32 zpse s 0x000000 voltage gain adjustment. 0x4381 iagain r/w 24 32 zpse s 0x000000 curren t channel a current gain adjustment. 0x4382 ibgain r/w 24 32 zpse s 0x000000 curren t channel b current gain adjustment. 0x4383 icgain r/w 24 32 zpse s 0x000000 curren t channel c current gain adjustment. 0x4384 idgain r/w 24 32 zpse s 0x000000 curren t channel d current gain adjustment. 0x4385 iegain r/w 24 32 zpse s 0x000000 curren t channel e current gain adjustment. 0x4386 ifgain r/w 24 32 zpse s 0x000000 current channel f current gain adjustment. 0x4387 reserved r/w 24 32 zpse s 0x000000 th is register should be ignored. 0x4388 dicoeff r/w 24 32 zpse s 0x000000 register used in the digi tal integrator algorithm. when the integrator is enabled, this register should be set to 0xfff8000. 0x4389 hpfdis r/w 24 32 zpse s 0x000000 disables the high-pass filter for all channels. 0x438a vrmsos r/w 24 32 zpse s 0x000000 voltage rms offset. 0x438b iarmsos r/w 24 32 zpse s 0x000000 current channel a current rms offset. 0x438c ibrmsos r/w 24 32 zpse s 0x000000 current channel b current rms offset. 0x438d icrmsos r/w 24 32 zpse s 0x000000 current channel c current rms offset. 0x438e idrmsos r/w 24 32 zpse s 0x000000 current channel d current rms offset. 0x438f iermsos r/w 24 32 zpse s 0x000000 current channel e current rms offset. 0x4390 ifrmsos r/w 24 32 zpse s 0x000000 current channel f current rms offset. 0x4391 awgain r/w 24 32 zpse s 0x000000 channel a active power gain adjust. 0x4392 awattos r/w 24 32 zpse s 0x000000 channel a active power offset adjust. 0x4393 bwgain r/w 24 32 zpse s 0x000000 channel b active power gain adjust. 0x4394 bwattos r/w 24 32 zpse s 0x000000 channel b active power offset adjust. 0x4395 cwgain r/w 24 32 zpse s 0x000000 channel c active power gain adjust. 0x4396 cwattos r/w 24 32 zpse s 0x000000 channel c active power offset adjust. 0x4397 dwgain r/w 24 32 zpse s 0x000000 channel d active power gain adjust 0x4398 dwattos r/w 24 32 zpse s 0x000000 channel d active power offset adjust. 0x4399 ewgain r/w 24 32 zpse s 0x000000 channel e active power gain adjust. 0x439a ewattos r/w 24 32 zpse s 0x000000 channel e active power offset adjust. 0x439b fwgain r/w 24 32 zpse s 0x000000 channel f active power gain adjust. 0x439c fwattos r/w 24 32 zpse s 0x000000 channel f active power offset adjust. 0x439d avargain r/w 24 32 zpse s 0x000000 channel a reactive power gain adjust. 0x439e avaros r/w 24 32 zpse s 0x000000 channel a reactive power offset adjust. 0x439f bvargain r/w 24 32 zpse s 0x000000 ch annel b reactive power gain adjust. 0x43a0 bvaros r/w 24 32 zpse s 0x000000 channel b reactive power offset adjust. 0x43a1 cvargain r/w 24 32 zpse s 0x000000 channel c reactive power gain adjust. 0x43a2 cvaros r/w 24 32 zpse s 0x000000 channel c reactive power offset adjust. 0x43a3 dvargain r/w 24 32 zpse s 0x000000 channel d reactive power gain adjust. 0x43a4 dvaros r/w 24 32 zpse s 0x000000 channel d reactive power offset adjust. 0x43a5 evargain r/w 24 32 zpse s 0x000000 channel e reactive power gain adjust. 0x43a6 evaros r/w 24 32 zpse s 0x000000 channel e reactive power offset adjust. 0x43a7 fvargain r/w 24 32 zpse s 0x000000 channel f reactive power gain adjust. 0x43a8 fvaros r/w 24 32 zpse s 0x000000 channel f reactive power offset adjust. 0x43a9 reserved this register should be ignored. 0x43aa reserved this register should be ignored. 0x43ab wthr1 r/w 24 32 zp u 0x000000 most significant 24 bits of the wthr[47:0] threshold. 0x43ac wthr0 r/w 24 32 zp u 0x000000 least significant 24 bits of the wthr[47:0] threshold.
ade7816 data sheet rev. 0 | page 38 of 48 address register name r/w 1 bit length bit length during communication 2 type 3 default value description 0x43ad varthr1 r/w 24 32 zp u 0x000000 most significant 24 bits of the varthr[47:0] threshold. 0x43ae varthr0 r/w 24 32 zp u 0x000000 least significant 24 bits of the varthr[47:0] threshold. 0x43af apnoload rw 24 32 zp u 0x000000 no load threshold in the active power datapath. 0x43b0 varnoload r/w 24 32 zpse s 0x000000 no load threshold in the reactive power datapath. 0x43b1 pcf_a_coeff r/w 24 32 zpse u 0x000000 phase calibration coefficient for channel a. set to 0x400c4a for a 50 hz system and 0x401235 for a 60 hz system. 0x43b2 pcf_b_coeff r/w 24 32 zpse u 0x000000 phase calibration coefficient for channel b. set to 0x400c4a for a 50 hz system and 0x401235 for a 60 hz system. 0x43b3 pcf_c_coeff r/w 24 32 zpse u 0x000000 phase calibration coefficient for channel c. set to 0x400c4a for a 50 hz system and 0x401235 for a 60 hz system. 0x43b4 pcf_d_coeff r/w 24 32 zpse u 0x000000 phase calibration coefficient for channel d. set to 0x400c4a for a 50 hz system and 0x401235 for a 60 hz system. 0x43b5 pcf_e_coeff r/w 24 32 zpse u 0x000000 phase calibration coefficient for channel e. set to 0x400c4a for a 50 hz system and 0x401235 for a 60 hz system. 0x43b6 pcf_f_coeff r/w 24 32 zpse u 0x000000 phase calibration coefficient for channel f. set to 0x400c4a for a 50 hz system and 0x401235 for a 60 hz system. 0x43b7 to 0x43bf reserved n/a n/a n/a n/a 0x000000 thes e registers should be ignored. 0x43c0 vrms r 24 32 zp s n/a voltage rms value. 0x43c1 iarms r 24 32 zp s n/a current channel a current rms value. 0x43c2 ibrms r 24 32 zp s n/a current channel b current rms value. 0x43c3 icrms r 24 32 zp s n/a current channel c current rms value. 0x43c4 idrms r 24 32 zp s n/a current channel d current rms value. 0x43c5 ierms r 24 32 zp s n/a current channel e current rms value. 0x43c6 ifrms r 24 32 zp s n/a current channel f current rms value. 0x43c7 to 0x43ff reserved these registers should be ignored. 1 r is read, and w is write. 2 for more information, see the register format section. 3 u indicates an unsigned register, and s indicates a signed register in twos complement format. table 13. run register address register name r/w 1 bit length bit length during communication type 2 default value description 0xe228 run r/w 16 16 u 0x0000 this regi ster starts and stops the dsp. 1 r is read, and w is write. 2 u indicates an unsigned register.
data sheet ade7816 rev. 0 | page 39 of 48 table 14. billable registers address register name r/w 1 bit length bit length during communication type 2 default value description 0xe400 awatthr r 32 32 s 0x00000000 channel a active energy accumulation. 0xe401 bwatthr r 32 32 s 0x00000000 channel b active energy accumulation. 0xe402 cwatthr r 32 32 s 0x00000000 channel c active energy accumulation. 0xe403 dwatthr r 32 32 s 0x00000000 channel d active energy accumulation. 0xe404 ewatthr r 32 32 s 0x00000000 channel e active energy accumulation. 0xe405 fwatthr r 32 32 s 0x00000000 channel f active energy accumulation. 0xe406 avarhr r 32 32 s 0x00000000 channel a reactive energy accumulation. 0xe407 bvarhr r 32 32 s 0x00000000 channel b reactive energy accumulation. 0xe408 cvarhr r 32 32 s 0x00000000 channel c reactive energy accumulation. 0xe409 dvarhr r 32 32 s 0x00000000 channel d reactive energy accumulation. 0xe40a evarhr r 32 32 s 0x00000000 channel e reactive energy accumulation. 0xe40b fvarhr r 32 32 s 0x00000000 channel f reactive energy accumulation. 1 r is read, and w is write. 2 s indicates a signed register in twos complement format. table 15. configuration and power quality registers address register name r/w 1 bit length bit length during communication 2 type 3 default value 4 description 0xe500 ipeak r 32 32 u n/a current peak register. 0xe501 vpeak r 32 32 u n/a voltage peak register. 0xe502 status0 r/w 32 32 u n/a interrupt status register 0. 0xe503 status1 r/w 32 32 u n/a interrupt status register 1. 0xe504 reserved r 20 32 zp u n/a this register should be ignored. 0xe505 reserved r 20 32 zp u n/a this register should be ignored. 0xe506 reserved r 20 32 zp u n/a this register should be ignored. 0xe507 oilvl r/w 24 32 zp u 0xffffff overcurrent threshold. 0xe508 ovlvl r/w 24 32 zp u 0xffffff overvoltage threshold. 0xe509 saglvl r/w 24 32 zp u 0x000000 voltage sag level threshold. 0xe50a mask0 r/w 32 32 u 0x00000000 interrupt enable register 0. 0xe50b mask1 r/w 32 32 u 0x00000000 interrupt enable register 1. 0xe50c iawv/idwv r 24 32 se s n/a instantaneous current channel a and instantaneous current channel d. 0xe50d ibwv/iewv r 24 32 se s n/a instantaneous current channel b and instantaneous current channel e. 0xe50e icwv/ifwv r 24 32 se s n/a instantaneous current channel c and instantaneous current channel f. 0xe50f reserved r 24 32 se s n/a th is register should be ignored. 0xe510 vwv r 24 32 se s n/a instantaneous voltage. 0xe511 to 0xe51e reserved r 24 32 se s n/a this register should be ignored. 0xe51f checksum r 32 32 u 0x33666787 checksum verification (see the checksum section for details). 0xe520 to 0xe52e reserved these registers should be ignored. 0xe600 chstatus r 16 16 u n/a channel peak register. 0xe601 angle0 r 16 16 u n/a time delay 0 (see the angle measurements section for details). 0xe602 angle1 r 16 16 u n/a time delay 1 (see the angle measurements section for details). 0xe603 angle2 r 16 16 u n/a time delay 2 (see the angle measurements section for details). 0xe604 to 0xe606 reserved these registers should be ignored.
ade7816 data sheet rev. 0 | page 40 of 48 address register name r/w 1 bit length bit length during communication 2 type 3 default value 4 description 0xe607 period r 16 16 u n/a line period. 0xe608 chnoload r 16 16 u n/a channel no load register. 0xe609 to 0xe60b reserved for proper operation, do not write to these addresses. 0xe60c linecyc r/w 16 16 u 0xffff line cycle accumulation mode count. 0xe60d zxtout r/w 16 16 u 0xffff zero-crossing timeout count. 0xe60e compmode r/w 16 16 u 0x01ff computation mode register. 0xe60f gain r/w 16 16 u 0x0000 pga gains at adc inputs (see table 22). 0xe610 to 0xe616 reserved this register should be ignored. 0xe617 chsign r 16 16 u n/a power sign register. 0xe618 config r/w 16 16 u 0x0000 configuration register. 0xe700 mmode r/w 8 8 u 0x1c measurement mode register. 0xe701 accmode r/w 8 8 u 0x00 accumulation mode register. 0xe702 lcycmode r/w 8 8 u 0x78 line accumulation mode. 0xe703 peakcyc r/w 8 8 u 0x00 peak detection half line cycles. 0xe704 sagcyc r/w 8 8 u 0x00 sag detection half line cycles. 0xe705 reserved this register should be ignored. 0xe706 hsdc_cfg r/w 8 8 u 0x00 hsdc configuration register. 0xe707 version r/w 8 8 u version of die. 0xe7e3 reserved r/w 8 8 u 0x00 register protection (see the register protection section). 0xe7fe reserved register protection key (see the register protection section). 0xebff reserved 8 8 this address can be used in manipulating the a a ss e e aa /hsa pin when spi is chosen as the active port (see the communication section for details). 0xec00 reserved this register should be ignored. 0xec01 config2 r/w 8 8 u 0x00 configuration register (see table 29). 1 r is read, and w is write. 2 32 zp is a 24- or 20-bit, signed or unsigned register that is transmitted as a 32-bit word with 8 or 12 msbs, respectively, pa dded with 0s. 32 se is a 24-bit, signed register that is transmitted as a 32-bit word that is sign extended to 32 bits. 3 u indicates an unsigned register, and s indicates a signed register in twos complement format. 4 n/a is not applicable. register descriptions table 16. hpfdis register (address 0x4389) bits default value description [23:0] 0x000000 when hpfdis = 0x000000, all high-pass filters in voltage and current channels are enabled. when the register is set to any nonzero value, all high-pass filters are disabled. table 17. ipeak register (address 0xe500) bits bit name default value description [31:27] reserved 0x00000 these bits should be ignored. 26 ipchannel2 0x0 the c or f current cha nnel generated the ipeakval[23:0] value. 25 ipchannel1 0x0 the b or e current cha nnel generated the ipeakval[23:0] value. 24 ipchannel0 0x0 the a or d current cha nnel generated the ipeakval[23:0] value. [23:0] ipeakval[23:0] 0x0 cu rrent channel peak value table 18. vpeak register (address 0xe501) bits bit name default value description [31:24] reserved 0x00000 these bits should be ignored. [23:0] vpeakval[23:0] 0x0 voltage channel peak value.
data sheet ade7816 rev. 0| page 41 of 48 note that address 0xe502, address 0xe503, address 0xe50a, and address 0xe50b are listed in table 30 and table 31 . table 19. chstatus register (address 0xe600) bits bit name default value description [15:6] reserved 0x000 these bits should be ignored. 5 oichannel2 0x0 the c or f current channel generated the overcurrent event. 4 oichannel1 0x0 the b or e current channel generated the overcurrent event. 3 oichannel0 0x0 the a or d current channel generated the overcurrent event. [2:0] reserved 0x000 reserved. these bits are always 0. table 20. chnoload register (address 0xe608) bits bit name default value description [15:6] reserved 0x0000000 these bits should be ignored. 5 noloadf 0x0 0: channel f is out of the no load condition. 1: channel f is in the no load condition. 4 noloade 0x0 0: channel e is o ut of the no load condition. 1: channel e is in the no load condition. 3 noloadd 0x0 0: channel d is o ut of the no load condition. 1: channel d is in the no load condition. 2 noloadc 0x0 0: channel c is out of the no load condition. 1: channel c is in the no load condition. 1 noloadb 0x0 0: channel b is out of the no load condition. 1: channel b is in the no load condition. 0 noloada 0x0 0: channel a is out of the no load condition. 1: channel a is in the no load condition. table 21. compmode register (address 0xe60e) bits bit name default value description 15 reserved 0x0 this bit should be ignored. 14 channel_sel 0x0 0: the a, b, and c current channels are used for the peak, overcurrent, zero crossing, angle, and waveform measurements. 1: the d, e, and f current channels are used for the peak, overcurrent, zero crossing, angle, and waveform measurements. [13:11] reserved 0x0 these bits should be ignored. [10:9] anglesel 0x00 00: the time delays betw een the voltage and currents are measured. 01: reserved. 10: the angles between current channels are measured. 11: no angles are measured. [8:0] reserved 0x1ff these bits should be ignored and not modified. table 22. gain register (address 0xe60f) bits bit name default value description [15:9] reserved 0x0000000 these bits should be ignored. [8:6] pga3[2:0] 0x000 gain selection for the d, e, and f current channels. 000: gain = 1. 001: gain = 2. 010: gain = 4. 011: gain = 8. 100: gain = 16. 101, 110, 111: reserved.
ade7816 data sheet rev. 0 | page 42 of 48 bits bit name default value description [5:3] pga2[2:0] 0x000 voltage channel gain selection. 000: gain = 1 001: gain = 2. 010: gain = 4. 011: gain = 8. 100: gain = 16. 101, 110, 111: reserved. gain selection for the a, b, and c current channels. 000: gain = 1. 001: gain = 2. 010: gain = 4. 011: gain = 8. 100: gain = 16. [2:0] pga1[2:0] 0x000 101, 110, 111: reserved. table 23. chsign register (address 0xe617) bits bit name default value description [15:7] reserved 0x0000000 these bits should be ignored. 0: the reactive power on the c or f channel is positive. 6 var3sign 0x0 1: the reactive power on the c or f channel is negative. 5 var2sign 0x0 0: the reactive power on the b or e channel is positive. 1: the reactive power on the b or e channel is negative. 4 var1sign 0x0 0: the reactive power on the a or d channel is positive. 1: the reactive power on the a or d channel is negative. 3 reserved 0x0 this bit should be ignored. 2 w3sign 0x0 0: the active power on the c or f channel is positive. 1: the active power on the c or f channel is negative. 1 w2sign 0x0 0: the active power on the b or e channel is positive. 1: the active power on the b or e channel is negative. 0 w1sign 0x0 0: the active power on the a or d channel is positive. 1: the active power on the a or d channel is negative. table 24. config register (address 0xe618) bits bit name default value description [15:8] reserved 0x0 these bits should be ignored. 7 swrst 0x0 initiates a software reset. 6 hsdcen 0x0 enables the hsdc serial port. [5:1] reserved 0x0 these bits should be ignored. 0 inten 0x0 enables the digital integrator. table 25. mmode register (address 0xe700) bits bit name default value description [7:5] reserved 0x000 these bits should be ignored. 4 peaksel2 0x1 the c or f current channe l is selected for peak detection. 3 peaksel1 0x1 the b or e current channe l is selected for peak detection. 2 peaksel0 0x1 the a or d current channel is selected for peak detection. [1:0] reserved 0x00 these bits should be ignored.
data sheet ade7816 rev. 0| page 43 of 48 table 26. accmode register (address 0xe701) bits bit name default value description 7 revrpsel 0x0 0: the sign of the reactive powe r is monitored on the a, b, and c channels. 1: the sign of the reactive power is monitored on the d, e, and f channels. 6 revapsel 0x0 0: the sign of the active power is monitored on the a, b, and c channels. 1: the sign of the active power is monitored on the d, e, and f channels. [5:4] reserved 0x00 these bits should be ignored and not modified. 00: signed accumulation for all reactive power measurements. 01: reserved. 10: reserved. [3:2] varacc[1:0] 0x00 11: reserved. [1:0] wattacc[1:0] 0x00 00: signed accumulation for all active power measurements. 01: reserved. 10: reserved. 11: reserved. table 27. lcycmode register (address 0xe702) bits bit name default value description 7 reserved 0x0 reserved. this bit does not control any functionality. 6 rstread 0x1 enables read-with-reset for all energy registers. no te that this bit has no function in line cycle accumulation mode and should be set to 0 when this mode is in use. [5:4] reserved 0x0 these bits should be ignored. 3 zx_sel 0x0 enables the voltage channel zero-crossi ng counter for line cycle accumulation mode. 2 reserved 0x0 these bits should be ignored. 1 lvar 0x0 enables the reactive energy line cycle accumulation mode. 0 lwatt 0x0 enables the active energy line cycle accumulation mode. table 28. hsdc_cfg register (address 0xe706) bits bit name default value description [7:6] reserved 0x00 these bits should be ignored. 5 hsapol 0x0 0: ss /hsa output pin is active low (default). 1: ss /hsa output pin is active high. [4:3] hxfer[1:0] 0x00 00 = reserved. 01 = hsdc transmits current and voltage waveform data. 10 = reserved. 11 = reserved. 2 hgap 0x0 0: no gap is introduc ed between packages (default). 1: a gap of seven hclk cycles is introduced between packages. 1 hsize 0x0 0: hsdc transmits the 32-bit registers in 32-bit packages, most signif icant bit first (default). 1: hsdc transmits the 32-bit registers in 8-bit packages, most significant bit first. 0 hclk 0x0 0: hsclk = 8 mhz (default). 1: hsclk = 4 mhz. table 29. config2 register (address 0xec01) bits bit name default value description [7:2] reserved 0x0 these bits should be ignored. 1 i2c_lock 0x0 serial port lock. 0 extrefen 0x0 set to 1 to use with an external reference.
ade7816 data sheet rev. 0 | page 44 of 48 interrupt enable and interrupt status registers table 30. status0 register (address 0xe5 02) and mask0 register (address 0xe50a) bits bit name default value description [31:18] reserved 0 0000 0000 0000 these bits should be ignored. 17 dready 0x0 new waveform data is ready. 16 reserved 0x0 this bit should be ignored. 15 reserved 0x0 this bit should be ignored. 14 reserved 0x0 this bit should be ignored. 13 reserved 0x0 this bit should be ignored. 12 revrp3 0x0 the sign of the reactive power has changed (c or f channel). 11 revrp2 0x0 the sign of the reactive power has changed (b or e channel). 10 revrp1 0x0 the sign of the reactive power has changed (a or d channel). 9 reserved 0x0 this bit should be ignored. 8 revap3 0x0 the sign of the active power has changed (c or f channel). 7 revap2 0x0 the sign of the active power has changed (b or e channel). 6 revap1 0x0 the sign of the active power has changed (a or d channel). 5 lenergy 0x0 the end of a line cycle accumulation period. 4 reserved 0x0 this bit should be ignored. 3 rehf2 0x0 the active energy register is half full (d, e, or f channel). 2 rehf1 0x0 the reactive energy register is half full (a, b, or c channel). 1 aehf2 0x0 the active energy register is half full (d, e, or f channel) 0 aehf1 0x0 the active energy register is half full (a, b, or c channel). table 31. status1 register (address 0xe5 03) and mask1 register (address 0xe50b) bits bit name default value description [31:25] reserved 0x0000000 these bits should be ignored. 24 pkv 0x0 the end of the voltage channel peak detection period. 23 pki 0x0 the end of the current channel peak detection period. 22 reserved 0x0 this bit should be ignored. 21 reserved 0x1 this bit should be ignored. 20 reserved 0x0 this bit should be ignored. 19 reserved 0x0 this bit should be ignored. 18 ov 0x0 an overvoltage event has occurred. 17 oi 0x0 an overcurrent event has occurred. 16 sag 0x0 a sag event has occurred. 15 rstdone 0x1 the end of a software or hardware reset. 14 zxi3 0x0 c or f current channel zero crossing. 13 zxi2 0x0 b or e current channel zero crossing. 12 zxi1 0x0 a or d current channel zero crossing. 11 reserved 0x0 this bit should be ignored. 10 reserved 0x0 this bit should be ignored. 9 zxv 0x0 voltage channel zero crossing. 8 zxtoi3 0x0 a zero crossing on the c or f current channel is missing. 7 zxtoi2 0x0 a zero crossing on the b or e current channel is missing. 6 zxtoi1 0x0 a zero crossing on the a or d current channel is missing. 5 reserved 0x0 this bit should be ignored. 4 reserved 0x0 this bit should be ignored. 3 zxtov 0x0 a zero crossing on the voltage channel is missing. 2 reserved 0x0 this bit should be ignored. 1 nload2 0x0 active and reactive no load co ndition on the d, e, or f current channel. 0 nload1 0x0 active and reactive no load co ndition on the a, b, or c current channel.
data sheet ade7816 rev. 0| page 45 of 48 outline dimensions 05-06-2011-a 0.50 bsc bottom view top view pin 1 indicator exposed pad p i n 1 i n d i c a t o r seating plane 0.05 max 0.02 nom 0.20 ref coplanarity 0.08 0.30 0.23 0.18 6.10 6.00 sq 5.90 0.80 0.75 0.70 for proper connection of the exposed pad, refer to the pin configuration and function descriptions section of this data sheet. 0.45 0.40 0.35 0.25 min 4.45 4.30 sq 4.25 compliant to jedec standards mo-220-wjjd. 40 1 11 20 21 30 31 10 figure 48. 40-lead lead frame chip scale package [lfcsp_wq] 6 mm 6 mm body, very very thin quad (cp-40-10) dimensions shown in millimeters ordering guide model 1 temperature range package description package option ade7816acpz ?40c to +85c 40-lead lfcsp_wq cp-40-10 ade7816acpz-rl ?40c to +85c 40-lead lfcsp_wq cp-40-10 EVAL-ADE7816EBZ evaluation board 1 z = rohs compliant part.
ade7816 data sheet rev. 0 | page 46 of 48 notes
data sheet ade7816 rev. 0| page 47 of 48 notes
ade7816 data sheet rev. 0 | page 48 of 48 notes i 2 c refers to a communications protocol originally developed by philips semiconductors (now nxp semiconductors). ?2012 analog devices, inc. all rights reserved. trademarks and registered trademarks are the property of their respective owners. d10390-0-2/12(0)

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