Modbus

TagSource example

{
  "protocol": "modbusTcp",
  "host": "127.0.0.1",
  "port": 502,
  "unitId": 1,
  "address": 4000,
  "encoding": "uint16",
  "byteOrder": "abcd",
  "area": "holding",
  "transport": "tcp"
}

Fields

Field	Required	Note
host, port, address	yes
unitId / slaveId	no	default 1
encoding	no	uint16 (default), int32, float32
byteOrder	no	abcd (default), dcba, badc, cdab
area	no	holding (default), input, coil, discrete
transport	no	tcp (default), rtu, rtuTcp
feedbackAddress, clockAddress, stringBytes	no
baudRate/parity/dataBits/stopBits	RTU	for rtu

Connection: host, port, unitId, transport, serial fields.
Point: address, encoding, byteOrder, feedbackAddress, area, clockAddress, stringBytes.

Read / write

• Read: FC03, FC04, FC01, FC02
• Write: FC06, FC16, FC05, FC15, FC22; FC23 exists on TCP but poll/operate do not select it

For rtu, the host field opens e.g. COM3.