CODESYS Modbus TCP Architecture with 2 HMI's


I am working on converting an e!Cockpit project that contains two WAGO TP600 HMI’s (Used as Modbus Masters), that are also connected to a PFC200 (Modbus Slave).

In e!Cockpit, we used the WriteOnly with OnValueChange (Modbus Configurator) in order to avoid having Modbus Masters overwrite each other on the Slave device. Either HMI should be able to read/write to the same register on the PFC200 to operate the machine.

Does anyone have suggestions on the best way to accommodate two HMI’s with a CODESYS application?
We would like to stick with Modbus TCP to accommodate legacy systems.

Hi Mike,

is it possible to update your System from e!Cockpit to Codesys?
If it is, you can Upgrade your PFC to FW26 and then you could use the Datasource Manager from Codesys. Which is an OPC-UA Client but you can browse your application an choose your Variables.
You can find an Description from Codesys on this Link:

The Download-Links for Codesys,the Device Description Package and the neweset Firmware you’ll find here:

If you want to stay with e!cockpit, I would say an Modbus connection is a good way to do this Communication. I would not recommend using networkvariables.

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Thank you for your input, Michael.

Datasource Manager looks like a great option for new projects! The goal is to upgrade from e!C to CODESYS to v3.5, and also retain the Modbus functionality. This will save us some time by not having to change the program in the PFC200’s that are already in service, and allow us to replace legacy equipment that relies on Modbus with TP600’s.

I suppose the question I would also ask… Is there a CODESYS v3.5 version of the “OnValueChange” feature that was in the e!Cockpit Modbus configurator? We have tried to use the “Rising Edge Trigger” in the CODESYS Modbus configurator, but it’s a bit more cumbersome.

unfortunately this featere is not given in the CODESYS Modbus Configurator.