SLC 5/03 comm with Mitsubishi via RS485


Thread Starter

Tom Treat

I am wondering if anyone has notes for the AB end of this type of communication. The SLC 5/03 has an available DH 485 port. I would like to connect my Mitsubishi FX1n w/rs 485 module I need to pass two variables between them, but I do not know how. If someone has writen an application like this, I would appreciate the help. Thanks in advance.

Tom Treat

Colin Carpenter

Have you looked at the "Babel Box" protocol converter from Red Lion Controls? Might solve the problem?

Alan Hartwell

The main problem using the SLC 5/03 RS-485 port will be that only A-B protocols are supported. I am not familiar with what protocols the Mitsubishi supports. You might consider a third-party communications module in the SLC such as made by ProSoft Technologies ( see "": ). They support a wide range of protocols, one of which may cooperate with the Mitsubishi.

If high data speed is not a concern, you could use a discrete output on one PLC wired to a compatible discrete input on the other. You can simulate serial communications with appropriate ladder logic on both PLCs using shift registers
and timers. I have used this method successfully on widely disparate PLCs at a blazing 5 bits per second.

Steve Myres, PE

It might be easier for you to use an ASCII BASIC module. Then you can define the protocol, and program in BASIC rather than using MSG instructions.