71M6545 Datasheet, PDF (72/134 Pages) Maxim Integrated Products – Four-Quadrant Metering, Phase Metrology Processors Flash/RAM Size

Data Sheet 71M6545/H
PDS_6545_009
4.3 Systems Using 71M6xx3 Isolated Sensors and Current Shunts
Figure 27 shows a typical connection for current shunt sensors; using the 71M6xx3 (poly-phase) isolated
sensors. Note that one shunt current sensor is connected without isolation, which is the neutral current
sensor in this example (connected to pins IADC0-IADC1). Each 71M6xx3 device is electrically isolated
by a low-cost pulse transformer. The 71M6545/H current sensor inputs must be configured for remote
sensor communications, as described in 2.2.8. Flexible remapping using the I/O RAM registers
MUXn_SEL[3:0] allows the sequence of analog input pins to be different from the standard configuration
(a corresponding CE code must be used). See Figure 2 for the AFE configuration corresponding to Figure
27.
Shunt Resistor Sensors
C
NEUTRAL
B
A
LOAD
POWER SUPPLY
This system is referenced to Neutral
NEUTRAL
Pulse Transformers
C
B
A
MUX and ADC
IADC0
IADC1
} IN*
VADC10 (VC)
IADC6
IADC7
}
IC
VADC9 (VB)
IADC4
IADC5
}
IB
VADC8 (VA)
IADC2
IADC3
} IA
V3P3A V3P3SYS GNDA GNDD
PWR MODE
CONTROL
TERIDIAN
PB
71M6545/H REGULATOR
TEMPERATURE
SENSOR
VBAT_RTC
BATTERY
MONITOR
RTC
BATTERY
HOST
SPI_CKI
SPI_DI
SPI_DO
SPI_CSZ
XFER_BUSY
SAG
VREF
SERIAL PORT
RX
TX
FLASH
MEMORY
RAM
MPU
RTC
TIMERS
OSCILLATOR/
PLL XIN
XOUT
DIO, PULSES,
LEDs
DIO
ICE
T
SPI INTERFACE
M
U
COMPUTE
ENGINE
X
V3P3D
WPULSE
XPULSE
RPULSE
YPULSE
10/7/2010
32 kHz
24
DIO
I²C or µWire
EEPROM
PULSES ^{3.3 VDC}
*IN = Optional Neutral Current
Figure 27: System Using Three-Remotes and One-Local (Neutral) Sensor
72
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