A Modbus RS485 Application question.

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Thread Starter

Niloc

A Schneider PLC model TSX3722 Micro needs to communicate with a Solcon Softstarter of the RVS DX range via Modbus RS485.

A PCMCIA card model TSX SCP 1114 is installed in the Micro and uses the TSX SCP CM 4030 cable. This cable has a plug on one end that connects to the PCMCIA card. The other end has five cores that is normally connected to a TSX SCA 50 passive T-junction box. I’ve been told that the cable can get connected directly to the RS485 terminals on the Softstarter. I’ve been advised that the cores to use are the White/Green + and the Green/White -.

I'd like to find out if anyone has accomplished this communication using the same range of PLC's with the Solcon Softstarter or another RS485 device using the same PCMCIA card and cable configuration, that is without the TSX SCA 50. The cable connected directly to the device. I've been advised that on a run less than 50 meters no termination resistors are required.

One last question with regards to the Solcon unit or other Modbus devices. The term LOM (listen only mode) Does anyone know if the Solcon has such a mode and if so where does one change this mode to respond to Master requests.

Solutions or suggestions will be appreciated and can be directed to my email address [email protected]
 
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