1766-RM001A-EN-P MicroLogix 1400 Programmable Controllers ...

Protocol Configuration 621Modbus Error CodesUpon receiving a Modbus command that is not supported or improperlyformatted, the controller configured for Modbus RTU Slave will respondwith one of the exception codes listed in below:Modbus Error Codes Returned by Modbus RTU SlaveErrorCodeError Description TransmittedException Code (2)0 No error. none1 Function Code cannot Broadcast. The function does not support Broadcast. nothing transmitted2 Function Code not supported. The controller does not support this Modbus function or1subfunction.3 Bad Command Length. The Modbus Command is the wrong size. 34 Bad Length. The function attempted to read/write past the end of a data file. 35 Bad parameter The function cannot be executed with these parameters. 16 Bad File Type The file number being referenced is not the proper file type. 27 Bad File Number The file number does not exist 28 Bad Modbus Address The function attempted to access an invalid Modbus address. (1) 39 Table Write protected The function attempted to write to a read-only file. 310 File Access Denied Access to this file is not granted. 211 File Already Owned Data file is already owned by another process. 2(1) See on page 617 for valid Modbus memory mapping.(2) If Modbus Command is sent with a valid Broadcast address, then no exception reply will be sent for Error Codes 2…11.Modbus Error Codes in Modbus RTU Master MSG InstructionErrorCodeError Description ReceivedException Code81 Illegal Function The function code sent by the Master is not supported by the slave 1or has an incorrect parameter.82 Illegal Data Address The data address referenced in the Master command does not 2exist in the slave, or access to that address is not allowed.83 Illegal Data Value The data value being written is not allowed, either because it is 3out of range, or it is being written to a read-only address.84 Slave Device Failure An unrecoverable error occurred while the slave was attempting 4to perform the requested action.85 Acknowledge The slave has accepted the request, but a long duration of time 5will be required to process the request.86 Slave Device Busy The slave is currently processing a long-duration command. 6Publication 1766-RM001A-EN-P - October 2008