HMS-EN2MB-R Limited Config for EIP Assembly

We have bought some EN2MB-R units with the hope that that give a much better integration to the Rockwell PLC / Studio environment for Modbus devices.

However, the ability to customise the EIP assembly structure to match the actual data embedded into the modbus registers seems virtually nil. For example, with holding register data in Modbus there is only the option to read that data as individual 16-bit registers (fixed as “INT” type on the EIP side) or pairs of 16-but registers (fixed as “DINT” type on the EIP side).
There seems to be no ability to:

  • Interpret 2x16bit modbus registers as a Real/Float
  • Interpret a 16bit modbus register as a set of 16 Bools
  • Interpret a 16bit modbus register as a pair of SINTs
  • Interpret modbus data as unsigned instead of signed integer (of any type)

Which makes the EIP assembly have very little value-added vs what would be achievable if we had this flexibility. Even from just the self-documenting and diagnostic perspectives it would be extremely valuable, and obviously makes the processing in the Logix PLC much simpler to write and troubleshoot.

Are there plans to introduce any of this functionality in the EN2MB-R? It seems an obvious and significant improvement to the device.

Hi @RowdyDoc,

The Modbus protocol does not natively support data types other than bits and 16-bit words. Since this is a gateway, we handle the transfer of the data, but the interpretation of the data needs to be done in the PLC.

I agree that it would be convenient to have this functionality in the gateway, but I’m not aware of any plans to add it in the future. I can certainly mention it to they Anybus team, and see what they have to say.

Best Regards,