71m6521fe Maxim Integrated Products, Inc., 71m6521fe Datasheet - Page 83

• Manufacturer Part Number: 71m6521fe
• Description: Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

WxSUM_X is the Wh value accumulated for element ‘X’ in the last accumulation interval and can be computed based on the
specified LSB value.
For example with VMAX = 600V and IMAX = 208A, LSB (for WxSUM_X ) is 0.08356 µWh.
The Frequency measurement is computed using the Frequency locked loop for the selected phase.
IxSQSUM_X and VxSQSUM are the squared current and voltage samples acquired during the last accumulation interval.
INSQSUM_X can be used for computing the neutral current.
The RMS values can be computed by the MPU from the squared current and voltage samples as follows:
MAINEDGE_X is useful for implementing a real-time clock based on the input AC signal. MAINEDGE_X is the number of half-
cycles accounted for in the last accumulated interval for the AC signal.
TEMP_RAW may be used by the MPU to monitor chip temperature or to implement temperature compensation.
v1.0
Ix
Address
Address
0x76
0x72
0x75
0x71
RMS
0x7D
0x7E
0x79
0x77
0x73
0x78
0x74
CE
CE
=
IxSQSUM
WSUM_ACCUM
VAR0SUM_X
VAR1SUM_X
VSUM_ACCUM
W0SUM_X
W1SUM_X
V0SQSUM_X
V1SQSUM_X
I0SQSUM_X
I1SQSUM_X
Name
FREQ_X
Name
N
⋅
LSB
ACC
⋅
3600
⋅
Description
The sum of Watt samples from each wattmeter element (In_8 is the gain
configured by IA_SHUNT or IB_SHUNT).
LSB = 6.6952*10
The sum of VAR samples from each wattmeter element (In_8 is the gain
configured by IA_SHUNT or IB_SHUNT).
LSB = 6.6952*10
F
Instantaneous Energy Measurement Variables
Description
Fundamental frequency. LSB
The sum of squared current samples from each element.
LSB = 6.6952*10
The sum of squared voltage samples from each element.
LSB= 6.6952*10
These are roll-over accumulators for WPULSE and VPULSE
respectively.
S
© 2005-2008 TERIDIAN Semiconductor Corporation
Other Measurement Parameters
Vx
-13
-13
-13
-13
VMAX IMAX / In_8 Wh.
VMAX IMAX / In_8 Wh.
RMS
VMAX
IMAX
=
2
2
VxSQSUM
V
/ In_8
2
h
71M6521DE/71M6521FE
≡
2
2
F
A
32
S
2
h
≈
N
⋅
. 0
LSB
ACC
587
⋅
3600
⋅
10
Energy Meter IC
−
⋅
6
F
Hz
S
DATASHEET
JANUARY 2008
Page: 83 of 101