ModBusTCP to TwinCAT2 and TwinCAT3

I have a Beckhoff TwinCAT 2 plc. My goal is to set up comms to Ignition using the ModBus TCP driver. I would use another if suggested and it wouldn't require modification to the plc, OPC requires additions to the variable declarations. As best I can tell the connection is made but apparently, tag browsing is not supported. I have no idea how to set up a path to a tag or map tags. Any help would be greatly appreciated;

You need to know the Modbus addresses at which your tags are exposed. Then you can follow IA's addressing instructions to create tags manually with keyed-in OPC Item Paths.

If you absolutely cannot tolerate not having drag and drop from the OPC browser, you have two options:

  • Create address aliases using the Mapping feature of IA's driver, or

  • Switch to my Advanced Modbus driver. If you are careful, you could even use mine to conveniently configure all of your tags in trial mode, then switch back to IA's driver. Most features and address formats are compatible in both directions.

In all cases, you must know the modbus addresses and data formats of your Beckhoff tags.

Thank you for the prompt response. The goal is to communicate with the plc with as little work on the plc side as possible, I'm not against manually creating tags on the Ignition side. Some of the variables I need from the plc only show tagnames without addresses. I apologize for my ignorance.

I know nothing about Beckhoff. But the brands with which I am familiar that support Modbus, there are procedures to follow to make tags available at specific addresses. I doubt Beckhoff is much different in this respect.

You will not be able to avoid messing with the PLC, I suspect. Sorry.

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