2 three connected units, Modbus communication modules, Gnd b a gnd gnd rs485 – Xylem 205546 Modbus Communication Modules for Displays User Manual
Page 12: Unit #3, Unit #2, B a gnd pe plc unit #1, Figure 4. three connected units, Termination off on
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EN 6.81 Modbus Communication Module 205546 Manual 1212
2.1.5.2 Three Connected Units
This example illustrates connection, termination and ID configuration of three
units each with a communication module and a PLC.
GND
B
A
GND
GND
RS485
Termination OFF
ON
GND GNDB
PCB no.: 510327-xxx
Communication RS485
3V3
5V5
5V
RTS
Rx
Tx
3V3
GND
B
A
GND
GND
RS485
Termination OFF
ON
Unit #3
GND
B
A
GND
GND
RS485
Termination OFF
ON
GND GNDB
PCB no.: 510327-xxx
Communication RS485
3V3
5V5
5V
RTS
Rx
Tx
3V3
GND
B
A
GND
GND
RS485
Termination OFF
ON
Unit #2
GND
B
A
GND
GND
RS485
Termination OFF
ON
GND GNDB
PCB no.: 510327-xxx
Communication RS485
3V3
5V5
5V
RTS
Rx
Tx
3V3
GND
B
A
GND
GND
RS485
Termination OFF
ON
B
A
GND
PE
PLC
Unit #1
Figure 4. Three Connected Units
Modbus Communication Modules
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