Full duplex RS-485 communication using CP341


Thread Starter

A. Yousef


I've got a CP 341, and I need to communicate to a slave PLC through the CP 341 as a master using Modbus protocol. The problem is that the slave PLC has a 4-wire full duplex RS-485 interface, and in the S7 hardware configuration the CP 341 is designated as having two operating modes:

1. full-duplex (RS 422) four-wire operation.
2. half-duplex (RS 485) two-wire operation.

How can I communicate to the slave PLC? Anyone have any idea?

A. Yousef
Should not be a problem you can convert a 4 wire RS485 to a 2 wire easily.

On the 4 wire side link TX + to RX +, and then link TX- toRX- should work fine, common practice.