71M6533/71M6534 Data Sheet
FDS_6533_6534_004
The maximum time jitter is1/6 of the MUX cycle period (nominally 67 µs) and is independent of the num-
ber of pulses measured. Thus, if the pulse generator is monitored for one second, the peak jitter is 67
ppm. After 10 seconds, the peak jitter is 6.7 ppm. The average jitter is always zero. If it is attempted to
drive either pulse generator faster than its maximum rate, it will simply output at its maximum rate without
exhibiting any rollover characteristics. The actual pulse rate, using WSUM as an example, is:
WRATE ⋅WSUM ⋅ FS ⋅ X
,
RATE =
Hz
246
where FS = sampling frequency (2520.6 Hz), X = Pulse speed factor derived from the CE variables
PULSE_SLOW and PULSE_FAST.
Table 59: CE Pulse Generation Parameters
CE Ad-
Name
Default Description
dress
0x21
0x22
0x23
0x41
WRATE
KVAR
171
6448
2520
0
Kh = VMAX*IMAX*66.1782 / (In_8*WRATE*NACC*X) Wh/pulse.
Scale factor for VAR measurement.
PRE_SAMPS * SUM_CYCLES (NACC
SUM_PRE
APULSEW
)
Wh pulse (WPULSE) generator input to be updated by the MPU
when using external pulse generation. The output pulse rate is:
APULSEW * FS * 2-32 * WRATE * X * 2-14.
This input is buffered and can be updated by the MPU during a
conversion interval. The change will take effect at the begin-
ning of the next interval.
0x38
PULSEWIDTH
12
Register for pulse width control of XPULSE and YPULSE. The
maximum pulse width is (2*PULSEWIDTH+1)*(1/FS). The default
value will generate pulses of 10 ms width at FS = 2520.62 Hz.
0x42
0x43
0x44
0x45
0x46
0x47
0x48
APULSER
APULSEX
0
0
0
0
0
0
0
VARh (RPULSE) pulse generator input.
Pulse generator input for XPULSE output.
Pulse generator input for YPULSE output.
Roll-over accumulator for WPULSE.
APULSEY
WSUM_ACCUM
VSUM_ACCUM
SUM2_ACCUM
SUM3_ACCUM
Roll-over accumulator for RPULSE.
Roll-over accumulator for the XPULSE pulse output.
Roll-over accumulator for the YPULSE pulse output.
Other CE Parameters
Table 60 shows the CE parameters used for suppression of noise due to scaling and truncation effects.
Table 60: CE Parameters for Noise Suppression and Code Version
CE Ad-
Name
Default Description
dress
0x26
0x27
0x28
0x2A
0x2B
0x2C
QUANTA
QUANTB
0
0
0
0
0
0
These parameters are added in channel A to the Watt calcula-
tion to compensate for input noise and truncation.
LSB = (VMAX*IMAX / In_8) *1.04173*10-9 W
QUANTC
QUANT_VARA
QUANT_VARB
QUANT_VARC
These parameters are added to the VAR calculation for element
A and B to compensate for input noise and truncation.
LSB = (VMAX*IMAX / In_8) * 1.04173*10-9 W
98
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