Rs485; Table 2: Rs485: Pinout - Unitronics Vision 120 OPLC User Manual

RS485

Use RS485 to create a multi-drop network containing up to 32 devices.
Diagram
Pin #1
Note that when a port is set to RS485, both RS232 and RS485 can be used simultaneously if
flow control signals DTR and DSR are not used.
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Caution
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Table 2: RS485: Pinout
Note that the ports are not isolated. If the controller is used with a
non-isolated external device, avoid potential voltage that exceeds
± 10V.
To avoid damaging the system, all non-isolated device ports should
relate to the same ground signal.
Use shielded, twisted pair cables.
Minimize the stub (drop) length leading from each device to the bus.
Ideally, the main cable should be run in and out of the network
device.
Do not cross positive (A) and negative (B) signals.
Positive terminals must be wired to positive, and negative terminals
to negative.
Chapter 5: Communications
Pin Number Function
1 A signal (+)
2 (RS232 signal)
3 (RS232 signal)
4 (RS232 signal)
5 (RS232 signal)
6 B signal (-)
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