Could not read/write registers (Wago 750-880, Modbus)


I have a few tags in the Tags section of Ignition Designer. I can read physical I/O and read/write coils.
However, I am not able to read/write holding registers. For example, I want to read an integer variable that is declared in PLC program with address %MW0. According to Wago manual (p.58) this address corresponds to Modbus address 12288. I tried the following paths:

[Wago]HR12288 - invalid address
[Wago]HR768 - no result
[Wago]HR769 - no result
[Wago]C12289 - reading first bit

I would appreciate if you can provide some guidance on the issue.


Did you try HR12289?

Are there errors on the console or does the device just not respond?

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Yes. In this case system marks tag with red and sets the value to null.

Sorry, my bad. HR12289 works. Thanks for your help :slight_smile:

If you find all your addresses are offset by 1 like this, you can try setting the “one-based addressing” advanced property for your device to false.

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