Modbus RTU Error Codes

TYPE MODBUS_ERRORS :
(
    (* Modbus communication errors *)
    MODBUSERROR_NO_ERROR,             (* 0 *)
    MODBUSERROR_ILLEGAL_FUNCTION,         (* 1 *)
    MODBUSERROR_ILLEGAL_DATA_ADDRESS,         (* 2 *)
    MODBUSERROR_ILLEGAL_DATA_VALUE,             (* 3 *)
    MODBUSERROR_SLAVE_DEVICE_FAILURE,         (* 4 *)
    MODBUSERROR_ACKNOWLEDGE,                (* 5 *)
    MODBUSERROR_SLAVE_DEVICE_BUSY,         (* 6 *)
    MODBUSERROR_NEGATIVE_ACKNOWLEDGE,         (* 7 *)
    MODBUSERROR_MEMORY_PARITY,             (* 8 *)
    MODBUSERROR_GATEWAY_PATH_UNAVAILABLE,     (* A *)
    MODBUSERROR_GATEWAY_TARGET_DEVICE_FAILED_TO_RESPOND, (* B *)

    (* additional Modbus error definitions *)
    MODBUSERROR_CHARREC_TIMEOUT := 16#20,     (* 20 hex *)
    MODBUSERROR_ILLEGAL_DATA_SIZE,         (* 21 hex *)
    MODBUSERROR_ILLEGAL_DEVICE_ADDRESS,         (* 22 hex *)
    MODBUSERROR_ILLEGAL_DESTINATION_ADDRESS,        (* 23 hex *)
    MODBUSERROR_ILLEGAL_DESTINATION_SIZE,     (* 24 hex *)
    MODBUSERROR_NO_RESPONSE,                (* 25 hex *)

    (* Low level communication errors *)
    MODBUSERROR_TXBUFFOVERRUN := 102,         (* 102 *)
    MODBUSERROR_SENDTIMEOUT := 103,         (* 103 *)
    MODBUSERROR_DATASIZEOVERRUN := 107,         (* 107 *)
    MODBUSERROR_STRINGOVERRUN := 110,         (* 110 *)
    MODBUSERROR_INVALIDPOINTER := 120,         (* 120 *)
    MODBUSERROR_CRC := 150,             (* 150 *)

    (* High level PLC errors *)
    MODBUSERROR_INVALIDMEMORYADDRESS := 232,        (* 232 *)
    MODBUSERROR_TRANSMITBUFFERTOOSMALL         (* 233 *)
);
END_TYPE