71m6515h Maxim Integrated Products, Inc., 71m6515h Datasheet - Page 42

• Manufacturer Part Number: 71m6515h
• Description: 71m6515h Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

VASQSUM (0x3D), VBSQSUM (0x3E), VCSQSUM (0x3F)
VAH_A (0x06), VAH_B (0x07), VAH_C (0x08)
Since the VAh calculation involves the post-processor, these registers will not be functional when the CE_ONLY bit in the
CONFIG register is set.
VARH_A (0x03), VARH_B (0x04), VARH_C (0x05)
VPHASE_ABC (0x10)
VRMS_A (0x09), VRMS_B (0x0A), VRMS_C (0x0B)
Page: 42 of 57
These registers hold the sum of the squared voltage samples collected during the previous accumulation interval. The
values for VASQSUM, VBSQSUM, and VCSQSUM are provided directly by the CE and are not post-processed. The
magnitude of the accumulated samples is determined by:
These registers hold the apparent energy collected during the previous accumulation interval. The magnitude of the
accumulated samples is determined by:
These registers hold the reactive energy collected during the previous accumulation interval. The magnitude of the
accumulated samples is determined by:
This register holds the phase angle between the voltages of phases A/C and A/B. The LSB is one degree.
Bits 15-0: These bits (VPHASE_AC) hold the phase angle between VA and VC.
Bits 31-16: These bits (VPHASE_AB) hold the phase angle between VA and VB.
These registers hold the post-processed RMS voltage for each phase. Only the 16 most significant bits are used. The
magnitude of the values is determined by:
Since the RMS calculation involves the post-processor, these registers will not be functional when the CE_ONLY bit in the
CONFIG register is set.
If higher precision is required, the host must calculate the RMS voltages from the values in the VASQSUM, VBSQSUM, and
VCSQSUM registers.
LSB
LSB
LSB
LSB
=
=
=
=
. 6
. 9
. 9
VMAX
8781
SUM
4045
4045
Example: The register IRMS_C reads the value 2,079,670. Assuming IMAX to be 208A, and using the formula
above, we determine the RMS current of phase C to:
formula above, we determine the RMS voltage of phase B to:
I
Example: The register VRMS_B reads the value 425,778,000. Assuming VMAX to be 600V, and using the
V
RMS
RMS
⋅
10
_
⋅
⋅
10
CYCLES
10
=
9 −
2
=
. 9
VMAX
−
2079670
−
425778000
13
13
4045
VMAX
VMAX
In
In
⋅
⋅
V
10
. 6
_
IMAX
rms
_
8781
IMAX
⋅
8
. 6
8
−
13
8781
⋅
V
60
10
© 2005-2008 TERIDIAN Semiconductor Corporation
2
⋅
−
60
10
h
9
VARh
208
VAh
−
9
600
=
. 0
=
0385
226
.
A
85
V
Energy Meter IC
DATA SHEET
71M6515H
MARCH 2008
V1.4