Function Code 1: Read Coils Request 1 Byte 1 to 255 PLC Node Address 1 Byte 0x01 Function Code 2 Bytes 0x0000 to 0xFFFF Starting Address 2 Bytes 1 to 2000 Quantity of Coils Response 1 Byte 1 to 255 PLC Node Address 1 Byte 0x01 Function Code 1 Byte N = Quantity of coils / 8 Byte Count N Bytes Value(s) Coil Status Function Code 2: Read Discrete Inputs Request 1 Byte 1 to 255 PLC Node Address 1 Byte 0x02 Function Code 2 Bytes 0x0000 to 0xFFFF Starting Address 2 Bytes 1 to 2000 Quantity of Inputs Response 1 Byte 1 to 255 PLC Node Address 1 Byte 0x02 Function Code N = Quantity of inputs / 8 1 Byte Byte Count N Bytes Value(s) Input Status
Function Code 1: Read Coils Request PLC Node Address 1 Byte 1 to 255 Function Code 1 Byte 0x01 Starting Address 2 Bytes 0x0000 to 0xFFFF Quantity of Coils 2 Bytes 1 to 2000 Response PLC Node Address 1 Byte 1 to 255 Function Code 1 Byte 0x01 Byte Count 1 Byte N = Quantity of coils / 8 Coil Status N Bytes Value(s) Function Code 2: Read Discrete Inputs Request PLC Node Address 1 Byte 1 to 255 Function Code 1 Byte 0x02 Starting Address 2 Bytes 0x0000 to 0xFFFF Quantity of Inputs 2 Bytes 1 to 2000 Response PLC Node Address 1 Byte 1 to 255 Function Code 1 Byte 0x02 Byte Count 1 Byte N = Quantity of inputs / 8 Input Status N Bytes Value(s)
PI_ModbusE_4.0.2.80.docx