ADE7758ARW Analog Devices Inc, ADE7758ARW Datasheet - Page 52

• Manufacturer Part Number: ADE7758ARW
• Description: IC ENERGY METERING 24-SOIC
• Manufacturer: Analog Devices Inc

Specifications of ADE7758ARW

• Rohs Status: RoHS non-compliant
• Input Impedance: 380 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.8V
• Current - Supply: 8mA
• 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
• Lead Free Status / RoHS Status: Not Compliant

ADE7758
where PHCAL_LSB_Weight is 1.2 μs if the %Error is negative
or 2.4 μs if the %Error is positive (see the Phase Compensation
section).
If it is not known, the line period is available in the ADE7758’s
frequency register, FREQ (0x10). To configure line period
measurement, select the phase for period measurement in the
MMODE[1:0] and set LCYCMODE[7]. Equation 72 shows how
to determine the value that needs to be written to xPHCAL
using the period register measurement.
Example: Phase Calibration Using Line Accumulation
This example shows only Phase A phase calibration. All three
PHCAL registers can be calibrated simultaneously using the
same method.
For this example, I
inductive, and Frequency = 50 Hz. Also, LINECYC = 0x800.
xPHCAL
Phase
Error
=
×
TEST
PHCAL
= 10 A, V
_
9
6 .
LSB
μs
NOM
_
Weight
= 220 V, Power Factor = 0.5
READ ALL xVARHR
AFTER LENERGY
×
Figure 83. Power Offset Calibration Using Line Accumulation
FREQ
FOR STEP 8
INTERRUPT
360
[
11
°
:
] 0
STEP 1
STEP 2
STEP 3
STEP 4
REGISTERS AFTER
STEP 5
xWATTOS FOR ALL
STEP 6
STEP 7
REPEAT STEP 3 TO
FOR I
MASK REGISTERS
PF = 0, INDUCTIVE
STEP 8
xVARHR, xVAROS
SET UP SYSTEM
SET UP SYSTEM
RESET STATUS
FOR I
WRITE TO ALL
LINECYC AND
CALIBRATION
(72)
Rev. D | Page 52 of 72
SET MMODE,
LCYCMODE,
CALCULATE
REGISTERS
STEP 8 FOR
INTERRUPT
REGISTER
READ ALL
xWATTHR
LENERGY
xWATTOS
@ PF = 1
PHASES
TEST
MIN
, V
, V
NOM
NOM
@
With I
ADE7758 meter shows 7318d in the AWATTHR (0x01) register.
For unity power factor (after gain calibration), the meter shows
14804d in the AWATTHR register. This is equivalent to
−1.132% error.
The Phase Error in degrees using Equation 66 is 0.374°.
Using Equation 72, the value written to APHCAL (0x3F), if at
50 Hz, the FREQ (0x10) register = 2085d, is 17d. Note that a
PHCAL_LSB_Weight of 1.2 μs is used because the %Error is
negative.
FOR STEP 8, CALCULATE
xVAROS FOR ALL PHASES
FOR STEP 8, WRITE TO
ALL xVAROS REGISTERS
Phase
Error
APHCAL
TEST
END
, V
=
Error
NOM
7318
=
, and 0.5 inductive power factor, the example
14804
( )
. 0
°
–
374
2
=
14804
–Arc
°
2
×
1
9
2 .
sin
6 .
=
−
×
⎛ −
⎜
⎝
. 0
2085
360
01132
. 0
01132
3
=
17
=
−
⎞
⎟
⎠
=
. 1
=
x 0
132
. 0
11
374
%
°