71M6541F Maxim, 71M6541F Datasheet - Page 130

• Manufacturer Part Number: 71M6541F
• Description: The 71M6541D/71M6541F/71M6541G/71M6542F/71M6542G are Teridian™ 4th-generation single-phase metering SoCs with a 5MHz 8051-compatible MPU core, low-power RTC with digital temperature compensation, flash memory, and LCD driver
• Manufacturer: Maxim

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:
•
•
•
5.3.8.1 Fundamental Energy Measurement Variables
Table 85
variables are signed 32-bit integers. Accumulated variables such as WSUM are internally scaled so they
have at least 2x margin before overflow when the integration time is one second. Additionally, the hardware
does not permit output values to fold back upon overflow.
71M6541D/F/G and 71M6542F/G Data Sheet
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
Address
Note:
†
Address
Note:
†
WSUM_X (CE RAM 0x84) and VARSUM_X (CE RAM 0x88) are the signed sum of Phase-A and Phase-B Wh
or VARh values according to the metering equation specified in the I/O RAM control field EQU[2:0] (I/O
RAM 0x2106[7:5]). WxSUM_X (x = 0 or 1, CE RAM 0x85 and 0x86) is the Wh value accumulated for phase x
in the last accumulation interval and can be computed based on the specified LSB value.
130
71M6542 only.
71M6542 only.
0x84
0x88
0x84
0x88
0x8A
0x8A
0x85
0x86
0x89
0x85
0x86
0x89
CE
CE
Fundamental energy measurement variables
Instantaneous (RMS) values
Other measurement parameters
†
†
†
†
and
VAR0SUM_X
VAR1SUM_X
VAR0SUM_X
VAR1SUM_X
VARSUM_X
VARSUM_X
W0SUM_X
W1SUM_X
W0SUM_X
W1SUM_X
Table 86
WSUM_X
WSUM_X
Name
Name
describe each transfer variable for fundamental energy measurement. All
Table 86: CE Transfer Variables (with Remote Sensor)
Table 85: CE Transfer Variables (with Local Sensors)
The signed sum: W0SUM_X+W1SUM_X. Not used
for EQU[2:0] = 0 (I/O RAM 0x2106[7:5]) and
EQU[2:0] = 1.
The sum of Wh samples from each wattmeter
element.
The signed sum: VAR0SUM_X+VAR1SUM_X. Not
used for EQU[2:0] = 0 and EQU[2:0] = 1.
The sum of VARh samples from each wattmeter
element.
The signed sum: W0SUM_X+W1SUM_X. Not used
for EQU[2:0] = 0 (I/O RAM 0x2106[7:5]) and
EQU[2:0] = 1.
The sum of Wh samples from each wattmeter
element.
The signed sum: VAR0SUM_X+VAR1SUM_X. Not
used for EQU[2:0] = 0 and EQU[2:0] = 1.
The sum of VARh samples from each wattmeter
element.
LSB
LSB
LSB = 1.55124*10
LSB = 1.55124*10
W
W
= 9.4045*10
= 9.4045*10
Description
Description
-12
-12
-13
-13
* VMAX* IMAX Wh.
*VMAX* IMAX VARh.
* VMAX * IMAX Wh.
* VMAX * IMAX VARh.
Figure 35
Figure 37
Figure 36
Figure 38
Configuration
Configuration
(page 93)
(page 95)
(page 94)
(page 96)
Rev 2