71M6533/71M6534 Data Sheet
FDS_6533_6534_004
Instantaneous Energy Measurement Variables
IxSQSUM_X and VxSQSUM are the squared current and voltage samples acquired during the last accumu-
lation interval. INSQSUM_X can be used for computing the neutral current.
Table 56: CE Energy Measurement Variables
CE Ad-
Name
Description
dress
0x8F
0x90
0x91
I0SQSUM_X
I1SQSUM_X
I2SQSUM_X
The sum of squared current samples from each element.
LSBI = 9.4045*10-13 IMAX2 / In_82 A2h
The sum of squared current samples from the calculated neutral:
(I + I + I )2
0x92
INSQSUM_X
∑
0
1
2
LSB=9.4045*10-13 IMAX2 / In_82 A2h
0x99
0x9A
0x9B
0x9C
0x93
0x94
0x95
I0SQRES_X
I1SQRES_X
I2SQRES_X
INSQRES_X
V0SQSUM_X
V1SQSUM_X
V2SQSUM_X
Residual current measurements with double-precision accuracy. The
exact current is:
ISQn = InSQSUM_X + InSQRES_X
The sum of squared voltage samples from each element.
LSBV= 9.4045*10-13 VMAX2 V2h
The RMS values can be computed by the MPU from the squared current and voltage samples as follows:
IxSQSUM ⋅ LSBI ⋅3600⋅ FS
VxSQSUM ⋅ LSBV ⋅3600 ⋅ FS
IxRMS
=
VxRMS =
NACC
NACC
Other Transfer variables include those available for frequency and phase measurement, and those re-
flecting the count of the zero-crossings of the mains voltage and the battery voltage. These transfer va-
riables are listed in Table 57.
MAINEDGE_X reflects the number of half-cycles accounted for in the last accumulated interval for the AC
signal of the phase specified in the FREQSEL1 and FREQSEL0 registers. MAINEDGE_X is useful for im-
plementing a real-time clock based on the input AC signal.
Table 57: Other Transfer Variables
CE Ad-
Name
Description
dress
0x82
0x97
FS
232
≡
≈ 0.587 ⋅10−6
FREQ_X
Fundamental frequency: LSB
Hz
PH_AtoB_X
Voltage phase lag. The selection of the reference phase is based on
FREQSEL1 and FREQSEL0 in the CECONFIG register:
If FREQSEL1/FREQSEL0 select phase A: Phase lag from A to B.
If FREQSEL1/FREQSEL0 select phase B: Phase lag from B to C.
If FREQSEL1/FREQSEL0 select phase C: Phase lag from C to A.
The angle in degrees is (0 to 360): PH_AtoB_X * 360/NACC + 2.4
96
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