SLC500 Communications with Unitronics PLC


Thread Starter



My client has two SLC500 PLCs connected to HMI on dh485 network. We are adding to the system an Unitronics V570 PLC and want to make this the main screen. The screen must control the outputs on the SLC500s and respond to inputs from the SLC500s. What will the best solution be for a network between the various PLCs?

Any suggestions will be appreciated.


PLC Programmer

If there exist an option for interface between SLC500 and the new PLC with an Ethernet, it would be the best solution.

Controlling the other PLC means the new PLC should control the Inputs to the old one.

Can be achieved through direct interface like Ethernet / HART. Or you could connect some Outputs of the New PLC to Di of old, instead of the DI triggers already provided to the old one.

Hope this helps..

Jeremy Pollard

I think the simplest thing to implement here would be Modbus. The Unitronics can be a Modbus master (or a slave).

The SLC's can be setup as Modbus RTU's. lots of assumptions here but worth checking out

Cheers from: Jeremy Pollard, CET The Caring Canuckian!
Crisis, necessity, change


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