Eaton easyE4 series Manual page 560

11. Connection to other devices
11.4 Modbus TCP
556
Unknown function:
If the client requests an unsupported function, the Modbus TCP server must return the
following error frame after receiving the request:
Fault Code 1 byte 0x80 + Function code
Exception Code 1 byte 01
This will indicate to the client that the desired function is not supported by the server.
easyE4 11/18 MN050009 EN www.eaton.com