AB 7632 Big vs Little endian configuration

I have a gateway that was installed in a Allen Bradley PLC system.

The gateway is producing modbus values but these are values that do not make any sense. Our customer believes that it could be an issue with configuration. Their control center can only read big endian values but they believe that it may be outputting in little endian format. Is there any to change this in the gateway configuration? I couldn’t find anything in any of the manual for this gateway.


It’s not possible to change the endianness on the Ethernet/IP side of this gateway. Because it’s an adapter/slave on both interfaces, it doesn’t have control of where the data is mapped. It’s mapped by the PLC on the Ethernet/IP side and the Modbus master on the Modbus side. I think you are going to have to swap the bytes in the PLC program.


No, with the AB7669, 16 and 32 bit values are automatically stored in Motorola (big endian) format which should be correct for Modbus. Can you provide specifics of the problem?

In this case please refer to my previous answer.