71M6541D Datasheet, PDF (93/166 Pages) Maxim Integrated Products – 0.1% Accuracy Over 2000:1 Current Range Energy Meter ICs

71M6541D/F/G and 71M6542F/G Data Sheet
4.3 71M6541D/F/G Using Local Sensors
Figure 35 shows a 71M6541D/F/G configuration using locally connected current sensors. The IAP-IAN
current channel may be directly connected to either a shunt resistor or a CT, while the IBP-IBN channel is
connected to a CT and is therefore isolated. This configuration implements a single-phase measurement
with tamper-detection using one current sensor to measure the neutral current. This configuration can
also be used to create a split phase meter (e.g., ANSI Form 2S). For best performance, both the IAP-IAN
and IBP-IBN current sensor inputs are configured for differential mode (i.e., DIFFA_E = 1 and DIFFB_E =
1, I/O RAM 0x210C[4] and 0x210C[5]). The IBP-IBN input must be configured as an analog differential
input disabling the remote sensor interface (i.e., RMT_E = 0, I/O RAM 0x2709[3]). See Figure 2 for the AFE
configuration corresponding to Figure 35.
CT
NEUTRAL
LINE
CT ^or
Shunt
LOAD
Note:
This system is referenced to LINE
NEUTRAL
LINE
POWER SUPPLY
AMR
IR
HOST
MUX and ADC V3P3A V3P3SYS _{GNDA GNDD}
IAP
PWR MODE
IAN
CONTROL
TERIDIAN ^WAKE-UP
71M6541D/F REGULATOR
VBAT
VA
VBAT_RTC
IBP
TEMPERATURE ^BATTERY
IBN
SENSOR
MONITOR
VREF
SERIAL PORTS
TX
RX
MODUL- _RX
ATOR _TX
POWER FAULT
COMPARATOR
SPI INTERFACE
RAM
COMPUTE
ENGINE
FLASH
MEMORY
MPU
RTC
TIMERS
ICE
COM0...5
SEG
SEG/DIO
LCD DRIVER
DIO, PULSES
DIO
V3P3D
OSCILLATOR/
PLL
XIN
XOUT
11/5/2010
Figure 35. 71M6541D/F/G with Local Sensors
BATTERY
RTC
BATTERY
LCD DISPLAY
8888.8888
PULSES,
DIO
I²C or µWire
EEPROM
32 kHz