Rainbow Electronics 71M6542G - Manual (Page 95)

v1.1 © 2008–2011 Teridian Semiconductor Corporation 95
4.5 71M6542F Using Local Sensors
Figure 38 shows a 71M6542F 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 dual-phase measurement
utilizing Equation 2. 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 4 for the AFE configuration corresponding to
Figure 38 .
MPU
RTC
TIMERS
IAP
VA
IBP
XIN
XOUT
RX
TX
TX
RX
COM0...5
V3P3A V3P3SYS
VBAT
VBAT_RTC
SEG
GNDA GNDD
SEG/DIO
DIO
ICE
PHASE A
NEUTRAL
LOAD
8888.8888
PULSES,
DIO
IR
AMR
POWER FAULT
COMPARATOR
MODUL-
ATOR
SERIAL PORTS
OSCILLATOR/
PLL
MUX and ADC
LCD DRIVER
DIO, PULSES
COMPUTE
ENGINE
FLASH
MEMORY
RAM
32 kHz
REGULATOR
Shunt
POWER SUPPLY
TERIDIAN
71M6542F
TEMPERATURE
SENSOR
VREF
BATTERY
PWR MODE
CONTROL
WAKE-UP
PHASE A
I 2 C or µWire
EEPROM
IAN
IBN
RTC
BATTERY
V3P3D
BATTERY
MONITOR
SPI INTERFACE HOST
LCD DISPLAY
Resistor Dividers
PHASE B
LOAD
VB
NEUTRAL
PHASE A
Shunt
Note:
This system is referenced to PHASE A
11/5/2010
CT or
Figure 37: 71M6542F with Local Sensors