UG-1098 ADE9000 Technical Reference Manual
Rev. 0 | Page 52 of 86
POWER CALIBRATION
APGAIN is the gain calibration register for Phase A. The active,
reactive, and apparent powers in each phase have a common
gain register and individual offset calibration registers.
1. Apply the nominal voltage and current at power factor = 1.
2. EP_CFG = 0x0011 and EGY_TIME = 7999 (1 sec
accumulation).
3. Read the AWATTHR_HI register.
4. The APGAIN register value is obtained as follows:
27
2
_
_
_
×
−
=
MEASURED
MEASURED
EXPECTED
HI
AWATTHR
HIAWATTHR
HIAWATTHR
APGAIN
AWATTHR_HI
EXPECTED
= I
FSP
× V
FSP
× Full-Scale Power Codes ×
Accumulation Time × 8000 × 2
−13
= 0.0947 × 0.311 × 20,694,066 × 1 sec × 8000 × 2
−13
= 595,191
Let AWATTHR_HI
MEASURED
= 580,000:
0x35A3D335153472
000,580
000,580595,191
27
==×
−
=APGAIN
Like the rms offset calibration, the power offset calibration is
performed with a small current at 5000:1 or less dynamic range.
In this example, the offset calibration current is 20 mA and the
voltage is 220 V.
1. Apply a nominal voltage and offset calibration current at
power factor = 1.
2. EP_CFG = 0x0013 and EGY_TIME = 1000 (10 sec
accumulation).
3. Read the AWATTHR_HI register.
4. AWATTOS is calculated as
13
2
__
−
×
×
−
=
DSP
MEASURED
EXPECTED
f
TimeonAccumulati
HIAWATTHR
HIAWATTHR
AWATTOS
AWATTHR_HI
EXPECTED
= Icalibration
FSP
× V
FSP
× Full-Scale Power Codes ×
Accumulation Time × 8000 × 2
−13
= 0.0002 × 0.311 × 20,694,066 × 10 sec × 8000 × 2
−13
= 12570
0xA1161
2
800010
000
,1112570
13
==
××
−
=
−
AWATTOS
5. To compute AVAROS, apply a nominal voltage and offset
calibration current at power factor = 0.
Follow similar steps to obtain BPGAIN, BWATTOS, BVAROS,
CPGAIN, CWATTOS, an d C VAR O S.
CONVERSION CONSTANTS
Conversion constants are used to convert ADE9000 register
readings into physical parameters. When the device is calibrated
to the full-scale ADC codes given in Table 29, the conversion
constants for the example system are calculated as follows:
μArms/LSB0036.2
092,702,520.0947
1010
10
LSB
μArms
6
6
=
×
×
=
−×
×
=
codesRMSscaleFullI
Inominal
ConstantConversionCurrent
FSP
μVrms/LSB
4225.13
092
,
702,
52311.
0
10220
10
LSB
μVrms
6
6
=
×
×
=
−
×
×
=
codesRMS
scale
FullV
Vnominal
ConstantConversion
Voltage
FSP
/mVA)/LSBmWATT/mVAR(6097.3
066
,694,
20311.00947.0
1022010
10
LSB
/mVAmWATT/mVAR
3
3
=
××
××
=
−
××
××
=
codesRMS
scaleFullV
I
Vnominal
Inominal
Constant
ConversionPower
FSPFSP
VAHr)/LSB
VARHr/WATTHr/(
0268.1
36002066,694,20
311.0
0947.
0
1022010
36002
10
LSB
VAHrVARHr/WATTHr/
13
6
13
6
µ
µµ=
××××
××
=
××−×
×
××
=
µµµ
−
−
codesRMSscaleFullV
I
VnominalInominal
ConstantConversionEnergy
FSPFSP
The physical parameters are obtained by multiplying the
register readings with the respective conversion constants.
For example, if the AIRMS register reading is 10,540,400
decimal codes,
Phase A rms current (A rms)
= 2.0036 µA rms/LSB × 10,540,400
= 21.12 A rms
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