x/modbusWrite component: v0.37.0+ batch-writes Modbus points over TCP/RTU, using industry-standard Modicon traditional addresses. Routes to Success/Failure.

Unlike the imperative x/modbus (single Cmd/Address/Quantity), this component is point-table oriented and shares the same point structure and connection config as x/modbusRead.

Requires the extension library: rulego-components-iot (opens new window)

Configuration

Field	Type	Description	Default
server	string	Modbus server address (tcp://host:port or rtu:///dev/ttyUSB0)	tcp://127.0.0.1:502
unitId	uint8	Slave unit ID	1
points	array	Default write point table (see below). Points in msg.Data take precedence	none
tcpConfig	object	TCP config (timeout/certFile/certKeyFile/caFile)	none
rtuConfig	object	RTU serial config (speed/dataBits/parity/stopBits)	none
encodingConfig	object	Encoding (endianness/wordOrder for multi-register values)	big-endian high-word

Point table (points)

Field	Description
name	Point name
addr	Modicon address (1-based): 00001=Coil, 10001=Discrete Input, 30001=Input Register, 40001=Holding Register; extended 6-digit 400001+ = Holding Register
type	Data type: BOOL/UINT16/INT16/UINT32/INT32/UINT64/INT64/FLOAT32/FLOAT64
value	Write value (string form, e.g. "23.5", "true", "0x1F"), supports ${msg.xx} templates
endian	Multi-register byte order: ABCD/CDAB/BADC/DCBA

All fields support ${msg.xx} / ${metadata.xx} templates.

Write Rules

• Read-only areas rejected: 10001(Discrete Input) / 30001(Input Register) are read-only; writes fail
• BOOL writes only to Coil: BOOL type can only write 00001(Coil); registers have no atomic bit-write
• Multi-register types: UINT32/INT32/FLOAT32/UINT64/INT64/FLOAT64 span multiple registers, encoded by endian

Input/Output

• Input: msg.Data with point list [{"name","addr","type","value"}] (takes precedence over configured points)
• Output: Success/Failure (any point failure fails the batch)

Example

Configured default write points:

{
  "id": "modbus_write",
  "type": "x/modbusWrite",
  "configuration": {
    "server": "tcp://192.168.1.100:502",
    "unitId": 1,
    "points": [
      {"name": "setpoint", "addr": "40010", "type": "FLOAT32", "value": "${msg.targetTemp}"},
      {"name": "motor", "addr": "00001", "type": "BOOL", "value": "true"}
    ]
  }
}

On-demand write (msg.Data with point list, takes precedence):

[{"name": "setpoint", "addr": "40010", "type": "FLOAT32", "value": "50.5"}]

Related

• Read: x/modbusRead
• Universal write entry: x/iotWrite (driver=modbus)
• Imperative (legacy): x/modbus (kept)