ADE7754AR Analog Devices Inc, ADE7754AR Datasheet - Page 25

• Manufacturer Part Number: ADE7754AR
• Description: IC ENERY METER 3PHASE 24-SOIC
• Manufacturer: Analog Devices Inc

Specifications of ADE7754AR

• Input Impedance: 370 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.8V
• Current - Supply: 7mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-SOIC (0.300", 7.50mm Width)
• Meter Type: 3 Phase
• For Use With: EVAL-ADE7754EBZ - BOARD EVALAUTION FOR ADE7754
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: AD71049AR; AD71049AR

and voltage gain registers. See the Current RMS Calculation
and Voltage RMS Calculation sections. Only the effect of the
apparent power gain is shown on Figure 35. The minimum
output range is given when the apparent power gain register
content is equal to 800h and the maximum range is given by
writing 7FFh to the apparent power gain register. This can be
used to calibrate the apparent power (or energy) calculation
in the ADE7754 for each phase and the total apparent energy.
See the Total Apparent Power Calculation section.
Apparent Power Offset Calibration
Each rms measurement includes an offset compensation register
to calibrate and eliminate the dc component in the rms value.
See the Current RMS Calculation and Voltage RMS Calculation
sections. The voltage and current rms values are then multiplied
in the apparent power signal processing. Because no additional
offsets are created in the multiplication of the rms values, there
is no specific offset compensation in the apparent power signal
processing. The offset compensation of the apparent power
measurement in each phase is done by calibrating each indi-
vidual rms measurement.
TOTAL APPARENT POWER CALCULATION
The sum of the apparent powers coming from each phase gives
the total apparent power consumption. Different combinations
of the three phases can be selected in the sum by setting Bits 7
and 6 of the VAMode register (mnemonic VAMOD[1:0]). Figure 36
demonstrates the calculation of the total apparent power.
REV. 0
PHASE A
PHASE B
PHASE C
V
V
V
I
I
I
A
B
C
A
B
C
Figure 35. Apparent Power Calculation Output Range
AAPGAIN
BAPGAIN
CAPGAIN
Figure 36. Total Apparent Power Calculation
AVGAIN
BVGAIN
CVGAIN
V
ARMS
EC56D7h
13A929h
F2E48Fh
F97247h
D1B71h
68DB9h
00000h
+
V
APPARENT
CRMS
POWER
+
RMS
RMS
RMS
RMS
RMS
RMS
000h
%
V
V
2
ARMS
CRMS
VOLTAGE CHANNEL AND
CURRENT CHANNEL 0.5V/GAIN
7FFh 800h
24
24
24
+ 150% FS
+ 100% FS
+ 50% FS
– 50% FS
– 100% FS
– 150% FS
AVAGAIN
CVAGAIN
BVAGAIN
AVAGAIN[11:0]
TOTAL APPARENT
POWER SIGNAL
–25–
The total apparent power calculated by the ADE7754 depends on
the configuration of the VAMOD bits in the VAMode register.
Each term of the formula used can be disabled or enabled by the
setting VASEL bits, respectively, to Logic 0 or Logic 1 in the
VAMode register. The different configurations are described in
Table IV.
VAMOD VASEL0
0d
1d
2d
Note that V
the voltage and current channels RMS values of the corresponding
registers.
For example, for VAMOD = 1, the formula used to process the
apparent power is
The polyphase meter configuration determines which formula
should be used to calculate the apparent energy. The American
ANSI C12.10 standard defines the different configurations of
the meter. Table V describes which mode should be chosen for
different configurations.
ANSI
5S/13S
6S/14S
8S/15S
9S/16S
Different gain calibration parameters are offered in the ADE7754
to cover the calibration of the meter in different configurations.
The APGAIN, VGAIN, and VAGAIN registers have different
purposes in the signal processing of the ADE7754. APGAIN
registers affect the apparent power calculation but should be
used only for active power calibration. VAGAIN registers are
used to calibrate the apparent power calculation. VGAIN regis-
ters have the same effect as VAGAIN registers when VAMOD =
0 or 2. They should be left at their default value in these modes.
VGAIN registers should be used to compensate gain mismatches
between channels in VAMOD = 1.
As mentioned previously, the offset compensation of the phase
apparent power calculation is done in each individual rms mea-
surement signal processing. See the Apparent Power Offset
Calibration section.
Total Apparent Power V
+
+
V
(
V
CRMS
Table IV. Total Apparent Power Calculation
ARMS
ARMS
Meter Form
3-wire Delta
4-wire Wye
4-wire Delta
4-wire Wye
V
V
V
ARMS
ARMS
ARMS
Table V. Meter Form Configuration
×
+
2
I
, V
CRMS
V
× I
× I
× I
CRMS
BRMS
ARMS
ARMS
ARMS
×
, V
)



1
×
CRMS
=
+
I
VASEL1
+ V
+(V
/2
+ V
BRMS
CVAG
ARMS
2
BRMS
ARMS
ARMS
VAMOD
0
1
2
0
, I
12
I
BRMS
ARMS
×
× I
× I
+ V
×






1
, I
I
BRMS
BRMS
+
ARMS
CRMS
BRMS
BVAG
2
)
12
, and I
×
VASEL2
+ V
+ V
+ V
VASEL
3 or 5 or 6
7
7
7
ADE7754



1



CRMS
CRMS
CRMS
+
CRMS
AVAG
2
× I
× I
× I
12
represent
CRMS
CRMS
CRMS


