71m6513h-igt Maxim Integrated Products, Inc., 71m6513h-igt Datasheet - Page 67

• Manufacturer Part Number: 71m6513h-igt
• Description: 3-phase Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

The RMS values can be computed by the MPU from the squared current and voltage samples as per the formulae:
Other Measurement Parameters
PH_AtoB_X and PH_AtoC_X contain phase angle information between the phase voltages, depending on the setting of
FREQ_SEL, as shown in the table below. The phase angle information can be used for phase sequencing and error detection.
If the voltage at the selected phase is missing, the meter accuracy will be reduced.
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 of the phase specified in the FREQSEL register.
Page: 67 of 96
Ix
Address
0x4C
0x4D
0x4A
0x4B
0x4E
0x4F
0x5A
0x33
0x41
0x50
RMS
CE
=
To maintain accuracy, FREQ_SEL must be set to a phase with an active voltage. For example, in a system where
phase A is lost (which can be detected using the SAG bits or by comparing the voltage VA with a lower limit),
FREQ_SEL must be set to an alternative phase to maintain accuracy.
IxSQSUM
V0SQSUM_X
V1SQSUM_X
V2SQSUM_X
V3SQSUM_X
INSQSUM_X
I0SQSUM_X
I1SQSUM_X
I2SQSUM_X
FREQSEL
FREQ_X
Name
N
⋅
LSB
ACC
⋅
3600
Description
Selected phase for the frequency monitor, the phase-to-phase voltage
measurements, and voltage zero crossings:
Phase A: 0 (default)
Phase B: 1
Phase C: 2
Fundamental frequency. LSB
The sum of squared current samples from each element.
LSB = 9.4045*10
The sum of squared current samples from the calculated neutral:
LSB = 1.2539*10
The sum of squared voltage samples from each element.
LSB= 9.4045*10
The sum of squared voltage samples from the V3 input. If CAL_V3 =
8192, then LSB = 9.4045*10
∑
(
⋅
I
F
© 2005-2008 TERIDIAN Semiconductor Corporation
0
S
+
I
1
+
Vx
I
-13
-13
-12
RMS
2
)
VMAX
IMAX
IMAX
2
=
.
2
2
2
VxSQSUM
/ In_8
/ In_8
V
2
-13
h
≡
3-Phase Energy Meter IC
VMAX
2
2
2
F
A
A
32
S
2
2
h
h
≈
2
V
. 0
N
2
⋅
h or 9.4045*10
LSB
587
ACC
71M6513/71M6513H
⋅
⋅
10
3600
DATA SHEET
−
6
Hz
⋅
-13
F
S
IMAX
2
I
2
h
AUGUST 2008
V2.5