Communication protocol 73Exception codesThe adapter module supports the Modbus exception codes shownbelow.Communication profilesModbus is an application layer messaging protocol. It describeshow data is transferred between a master and a server, but not themeaning of that data. Communication profiles are used to definethe meaning of the data.ExceptionCode Name Description01h ILLEGAL FUNCTION The function code received in thequery is not an allowable action forthe server.02h ILLEGAL DATAADDRESSSThe data address received in thequery is to an allowable addressfor the server.03h ILLEGAL DATA VALUE A value contained in the query datafield is not an allowable value forthe server.04h SLAVE DEVICEFAILUREAn unrecoverable error occurredwhile the server was attempting toperform the requested action.06h SLAVE DEVICE BUSY The server is engaged inprocessing a long-durationcommand. The master shouldretransmit the message later whenthe server is free.
