Modbus TCP Configuration

I am having issues setting up the Modbus TCP to communicate with an AnyBus Communicator 7072. In the AB7072 I can see all the data that is being read from a device on Modbus. I am using Modbus Poll to verify that the AB7072 has the data available to read. The data all lines up.

I have configured a single tag to read a single the input register 2 in the AB7072. The OPC item path for the tag is [Modbus]1.IRF2. The tag is valid with a value of zero. If I change the OPC item path to read a HRF or a different node, the tag will become null and invalid. The tag becomes valid as soon as I change the OPC item path back. So I believe I am communicating with the AB7072 through the Modbus TCP device that I have configured. I know there are a bunch of different settings in the Modbus TCP device and I have changed some of the settings but the value of the tag stays at 0.

I have spent a lot of time trying to get this Modbus communication working. Any help would be greatly appreciated!!!

Did you check if you need to reverse word order? This is typical when trying to read a Float…indicated by the IRF command.

Are you sure that value is supposed to be a float?

If there is any value, float will pick some weird reading too.
Anyway, used a while ago the AnyBus gateway succesfully.Just need to be a little careful.
Holding and input are not same registers unless you want to.
If you are using Modbus Poll , and you see values then you should know if they are holding or input registers.
Also you know from gateway configuration if it’s one or zero addressing.
Suggest at start to create a configuration which will deliver one or two simple int registers. ( you will deal with float later)
Check values with gateway utility, after that with ModbusPoll. If all ok you can create an int tag to check value.( disable span gaps too )

Sorry for the delayed reply!

I have no idea why I thought it was a float. Changed the OPC item path to just an IR and data started flowing. That’s the thing with Modbus, every set-up is different. But once you figure out how the communication is suppose to be set up, it just works.

Thanks for all your help.

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ModbusTCP is not so bad after all. If you want some real fun try Modbus RTU spiced up with proprietary rules.