Fieldbus Communication • 125MODBUS FunctionsWAGO-I/O-SYSTEM 750ETHERNET TCP/IP4.2.3.5 Function Code FC5 (Write Coil)This function writes a single output bit to the slave device.RequestThe request specifies the reference number (output address) of output bit to bewritten. The reference number of the request is zero based; therefore, the firstcoil starts at address 0.Example: Turn ON the second output bit (address 1):Byte Field name ExampleByte 0, 1 Transaction identifier 0x0000Byte 2, 3 protocol identifier 0x0000Byte 4, 5 length field 0x0006Byte 6 unit identifier 0x01 not usedByte 7 MODBUS function code 0x05Byte 8, 9 reference number 0x0001Byte 10 ON/OFF 0xFFByte 11 0x00ResponseByte Field name Example.....Byte 7 MODBUS function code 0x05Byte 8, 9 Reference number 0x0001Byte 10 Value 0xFFByte 11 0x00ExceptionByte Field name Example.....Byte 7 MODBUS function code 0x85Byte 8 Exception code 0x01, 0x02 or 0x03
