71M6545 Datasheet, PDF (106/134 Pages) Maxim Integrated Products – Four-Quadrant Metering, Phase Metrology Processors Flash/RAM Size

Data Sheet 71M6545/H
PDS_6545_009
0x87
0x88
0x89
0x8A
0x8B
W2SUM_X
VARSUM_X
VAR0SUM_X
VAR1SUM_X
VAR2SUM_X
LSB_W = 1.0856*10^-12 VMAX IMAX Wh.
The signed sum:
VAR0SUM_X+VAR1SUM_X+VAR2SUM_X.
The sum of VARh samples from each wattmeter
element.
LSB_W = 1.0856*10^-12 VMAX IMAX VARh.
WSUM_X and VARSUM_X are the signed sum of Phase-A, Phase-B and Phase-C Wh or VARh values
according to the metering equation specified in the control field EQU[2:0] (I/O RAM 0x2106[7:5]).
WnSUM_X is the Wh value accumulated for phase n in the last accumulation interval and can be computed
based on the specified LSB value.
For example, with VMAX = 600 V and IMAX = 208 A, the LSB for WnSUM_X is 0.135 µWh.
5.4.8.1 Instantaneous Energy Measurement Variables
InSQSUM_X and VnSQSUM are the squared current and voltage samples acquired during the last accumulation
interval. INSQSUM_X can be used for computing the neutral current.
CE
Address
0x8C
0x8D
0x8E
0x8F
0x90
0x91
0x92
Table 72: CE Energy Measurement Variables (with Shunts)
Name
Description
Configuration
I0SQSUM_X
I1SQSUM_X
I2SQSUM_X
I3SQSUM_X
V0SQSUM_X
V1SQSUM_X
V2SQSUM_X
Neutral Current:
LSB_I = 9.9045*10^-13 * IMAX² A²h (PRE_E=0)
LSB_I = 6.1903125*10^-14 * IMAX² A²h (PRE_E=1)
LSB_I = 6.3968*10^-13 * (IMAX²) A²h
LSB_V = 9.4045*10^-13*VMAX² V²h
Figure 27 (page 72)
Table 73: CE Energy Measurement Variables (with CTs)
CE
Address
Name
Description
Configuration
0x8C
I0SQSUM_X
0x8D
0x8E
0x8F
I1SQSUM_X
I2SQSUM_X
I3SQSUM_X
LSB_I = 1.0856*10^-12 * (IMAX²) A²h
Figure 28 (page 73)
0x90
0x91
V0SQSUM_X
V1SQSUM_X
LSB_V = 1.0856*10^-12 * VMAX² V²h
0x92
V2SQSUM_X
The RMS values can be computed by the MPU from the squared current and voltage samples as follows:
Ix_RMS =
IxSQSUM ⋅ LSB_I ⋅ 3600 ⋅ F_S
N _ACC
Vx_RMS =
VxSQSUM ⋅ LSB_V ⋅ 3600 ⋅ F_S
N _ACC
106
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