Datasheet

71M6543F/71M6543G Data Sheet
v2 123
The RMS values can be computed by the MPU from the squared current and voltage samples as follows:
Other transfer variables include those available for frequency and phase measurement, and those reflecting
the count of the zero-crossings of the mains voltage and the battery voltage. These transfer variables are
listed in Table 82.
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 FREQSEL[1 :0] field of the CECONFIG register (CE RAM 0x20[7:6]) .
MAINEDGE_X is useful for implementing a real-time clock based on the input AC signal.
Table 82: Other Transfer Variables
CE
Address
Name Description
0x82
FREQ_X
Fundamental frequency: LSB
6
32
10509.0
2
2184
−
⋅≈≡
Hz
Hz(for CT)
LSB
6
32
10587.0
2
2520
−
⋅≈≡
Hz
Hz(for Shunt)
0x83
MAINEDGE_X
The number of edge crossings of the selected voltage in the previous
accumulation interval. Edge crossings are either direction and are
debounced.
0x94
PH_AtoB_X
Voltage phase lag. The selection of the reference phase is based on
FREQSEL[1:0] in the CECONFIG register:
If FREQSEL[1:0] selects phase A: Phase lag from A to B.
If FREQSEL[1:0] selects phase B: Phase lag from B to C.
If FREQSEL[1:0] selects phase C: Phase lag from C to A.
Angle in degrees is (0 to 360): PH_AtoB_X * 360/N
ACC
+ 2.4*15/13 (for CT)
Angle in degrees is (0 to 360): PH_AtoB_X * 360/N
ACC
+ 2.4 (for Shunt)
0x95
PH_AtoC_X
If FREQSEL[1:0] selects phase A: Phase lag from A to C.
If FREQSEL[1:0] selects phase B: Phase lag from B to A.
If FREQSEL[1:0] selects phase C: Phase lag from C to B.
Angle in degrees is (0 to 360): PH_AtoC_X * 360/N
ACC
+ 4.8*15/13 (for CT)
Angle in degrees is (0 to 360): PH_AtoC_X * 360/N
ACC
+ 4.8*15/13 (for Shunt)
Phase angle measurement accuracy can be increased by writing values > 1 into V_ANG_CNT
(V_ANG_CNT indicates how many accumulation periods to sum PH_AtoB_X and PH_AtoC_X
over. The MPU then has to divide by that number. For standard CE codes that support shunts
with remotes, V_ANG_CNT is at CE address 0x53. For standard CE codes that support shunts
with CT, V_ANG_CNT is at CE address 0x55. For other than standard CE codes, please contact
Maxim for information).
5.3.9 Pulse Generation
Table 83 describes the CE pulse generation parameters.
The combination of the CECONFIG PULSE_SLOW (CE RAM 0x20[0]) and PULSE_FAST (CE RAM 0x20[1])
bits controls the speed of the pulse rate. The default values of 0 and 0 maintain the original pulse rate
given by the Kh equation.
WRATE (CE RAM 0x21) controls the number of pulses that are generated per measured Wh and VARh
quantities. The lower WRATE is the slower the pulse rate for measured energy quantity. The metering
constant Kh is derived from WRATE as the amount of energy measured for each pulse. That is, if Kh =
ACC
SI
RMS
N
FLSBIxSQSUM
Ix
⋅⋅⋅
=
3600
ACC
SV
RMS
N
FLSBVxSQSUM
Vx
⋅⋅⋅
=
3600