71m6534h-igt Maxim Integrated Products, Inc., 71m6534h-igt Datasheet - Page 95

• Manufacturer Part Number: 71m6534h-igt
• Description: Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

FDS_6533_6534_004
4.3.8 CE Transfer Variables
When the MPU receives the XFER_BUSY interrupt, it knows that fresh data is available in the transfer
variables. CE transfer variables are modified during the CE code pass that ends with an XFER_BUSY
interrupt. They remain constant throughout each accumulation interval. In this data sheet, the names of
CE transfer variables always end with _X. The transfer variables can be categorized as:
1. Fundamental energy measurement variables
2. Instantaneous (RMS) values
3. Other measurement parameters
Fundamental Energy Measurement Variables
Table 55
32-bit integers. Accumulated variables such as WSUM are internally scaled so they have at least 2x mar-
gin before overflow when the integration time is one second. Additionally, the hardware will not permit
output values to fold back upon overflow.
WxSUM_X and VARSUM_X are the signed sum of Phase-A, Phase-B and Phase-C Wh or VARh values
according to the metering equation specified in the I/O RAM register EQU. WxSUM_X is the Wh value
accumulated for phase x in the last accumulation interval and can be computed based on the specified
LSB value.
For example, with VMAX = 600 V and IMAX = 208 A, the LSB for WxSUM_X is 0.1173 µWh.
v1.1
CE Ad-
CE Ad-
dress
0x8A
0x8B
0x8C
0x8D
0x85
0x86
0x87
0x88
dress
0x24
0x40
[0]
describes each transfer variable for fundamental energy measurement. All variables are signed
PULSE_SLOW
VAR0SUM_X
VAR1SUM_X
VAR2SUM_X
GAIN_ADJ
VARSUM_X
SAG_THR
W0SUM_X
W1SUM_X
W2SUM_X
WSUM_X
Name
Name
Table 54: Sag Threshold and Gain Adjust Control
© 2007-2009 TERIDIAN Semiconductor Corporation
2.39*10
Default
16384
Description
The signed sum: W0SUM_X+W1SUM_X+W2SUM_X.
The sum of Wh samples from each wattmeter element.
The signed sum: VAR0SUM_X+VAR1SUM_X+VAR2SUM_X.
The sum of VARh samples from each wattmeter element.
0
Table 55: CE Transfer Variables
LSB = 9.4045*10
LSB = 9.4045*10
7
ther 1 or 0. Default is 0 for both (X = 6).
PULSE_SLOW PULSE_FAST
Description
The voltage threshold for sag warnings. The default value is
equivalent to 80 V RMS if VMAX = 600 V.
This register scales all voltage and current channels. The
default value is equivalent to unity gain (1.000).
0
0
1
1
-13
-13
VMAX IMAX / In_8 Wh.
VMAX IMAX / In_8 VARh.
0
1
0
1
71M6533/71M6534 Data Sheet
1.5 * 2
1.5 * 2
1.5 * 2
Do not use
-4
X
= 0.09375
6
2
= 96
= 6
95