Sensor wiring, Modbus rs-485 wiring, Sensor communica ons modbus – APG PT-503 Slave Submersible Modbus user manual User Manual
Page 5: Modbus daisy-chain wiring

Rev. A, 5/13
PT-500 Submersible Pressure Sensor
5
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• Sensor Wiring
All PT-500 models will operate on 5-24 Vdc. Always use a high quality power
source that will deliver clean, stable voltage.
Modbus RS-485 Wiring
Always use shielded cable. APG recommends using twisted-pair cable for all
Modbus network wiring.
Power
Supply
Master
Device
RS-485 A
RS-485 B
Vdc
Vdc
+
-
Sensor 1
V+ V-
A B
Sensor 2
V+ V-
A B
Sensor 3
V+ V-
A B
Use Shielded Cable
120 Ohm
Terminating
Resistor
120 Ohm
Terminating
Resistor
Modbus Daisy-Chain Wiring
• Sensor Communica ons
Modbus
(RS-485)
The PT-500 u lizes standard Modbus RTU protocol (RS-485). The sensor can
only operate as a slave device. For more informa on about Modbus RTU,
please visit www.modbus.org.
With default se ngs, the sensor will transmit at: 9600 baud, 8 bits, 1 Stop Bit,
No parity.