Modbus TCP

Modbus TCP devices (inverters, meters, PLCs) that node bindings read registers from.

In the GUI

Integrations › Modbus TCP. + Add a connection per device, Save.

Modbus TCP page

Field	Setting	Default
ID	`Modbus.Connections[].Id`
Name	`Name`
Host	`Host`
Port	`Port`	`502`
Framing	`Framing`: `auto`, `tcp`, `rtu-over-tcp`	`auto`
Unit ID	`UnitId`	`1`
Poll Interval Seconds	`PollIntervalSeconds`	`10`
Timeout Ms	`TimeoutMs`	`1500`
Enabled	`Enabled`	on

Test connections reads each connection once.
Explore registers reads a block of registers and shows each decoding.
Bind a register on a node: Bindings.
Import device template on the Nodes page adds a connection and nodes for a known device.

Framing

Framing	Use
`auto`	Tries Modbus TCP, then RTU over TCP. The result is remembered.
`tcp`	Native Modbus TCP, usually port 502
`rtu-over-tcp`	RS485-to-Ethernet gateways, often port 4196 or 8899

Polling

One poller per device (host:port:unitId), in the worker role only.
The Nodes editor shows values from the worker's cache. Test device read opens a separate connection.

In YAML

Modbus:
  Connections:
    - Id: eg4
      Name: EG4 FlexBoss 21
      Host: 192.168.1.50
      Port: 8899
      Framing: rtu-over-tcp
      UnitId: 1
      PollIntervalSeconds: 10
EnergyFlow:
  Nodes:
    - Id: meter
      Label: Meter
      Sources:
        - { Type: modbus, Metric: realpower, Connection: eg4, Register: 0, RegisterType: holding, DataType: int32, WordOrder: big }

Register fields: Register (0-based), RegisterType (holding, input), DataType (uint16, int16, uint32, int32, float32), WordOrder (big, little).

All settings: Modbus reference.