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how to connect rs485 in PLC?

Last modified by Mora Zhou on 2023/11/21 16:18

RS485 & RS422

ItemsCOM1COM2
≥24 IO

RS485 or RS422

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RS485

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＜24IO

RS422

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RS485

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LX3V-1410 is with 24 IO, please refer to ≥24 IO in serial port.  LX3V-0806 is with 14IO only, you should refer to ＜24IO

Wiring diagram

RS485

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RS422

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LX3V-0806/LX3V-1208 plc only can support COM1 RS422 and COM2 RS485.

LX3V-0806/LX3V-1208 plc com2 rs485 port is in below.NoteLX3V-0806/LX3V-1208 plc can not support connect module.because it does not with module port)

2.PLC COM2(please check more detailed in modbus demo)

PLC COM2 could support Wecon PLC protocol and Modbus RTU protocol.So user need to set plc parameter in D8120 and D8126 to choose use which protocol.

For example(Wecon HMI connect Wecon PLC COM2 by Wecon PLC protocol)

HMI parameter is in the picture below.(Setting--->Communication)

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PLC program example.

D8120 means communication parameter format(9600,1,7,EVEN)---->D8120=10000110(2)=86(Hex)

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D8126=01H means use Wecon PLC protocol.

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