Modus Exception Codes
Exception Code | Name | Description |
|---|---|---|
01 | Illegal Function | The server does not recognize or permit the function code. |
02 | Illegal Data Address | The data address (register, discrete input or coil number) is not an permitted address for the server. If multiple registers were requested, at least one was not permitted. |
Reference: MODBUS Application Protocol Specification V1.1b3, April 26 2012
For more information refer to the Modbus organisation website.