Modbus Exception Codes

Exception codes returned by a Modbus server in an exception response when it cannot fulfil a client request. Defined in the Modbus Application Protocol Specification V1.1b3, section 7.

10 codes

• 1 ILLEGAL_FUNCTION
• 2 ILLEGAL_DATA_ADDRESS
• 3 ILLEGAL_DATA_VALUE
• 4 SERVER_DEVICE_FAILURE
• 5 ACKNOWLEDGE
• 6 SERVER_DEVICE_BUSY
• 7 NEGATIVE_ACKNOWLEDGE
• 8 MEMORY_PARITY_ERROR
• 10 GATEWAY_PATH_UNAVAILABLE
• 11 GATEWAY_TARGET_DEVICE_FAILED_TO_RESPOND