M-Bus
Connect an M-Bus meter over TCP or serial and read its values.
M-Bus (Meter-Bus) reads metering data — typically from energy, heat, water, and gas meters. You can connect over TCP (via a gateway) or a serial port, and address the meter by its primary or secondary address.
Connecting an M-Bus device
Common settings:
| Setting | What it does |
|---|---|
| Name | Identifies the device (with an optional custom name). |
| Enabled | Whether THMI connects to the device. Turn it off to stop communication and value collection without deleting it. |
Connection: TCP or serial
Choose the connection type:
- TCP — connect through a gateway with a host, port (default 2000), and timeout (default 5 seconds).
- Serial — connect over a serial port with a port name, a baud rate (300, 600, 1200, 2400, 4800, or 9600 — default 2400), and parity (None, Even, or Odd). These must match how the meter’s serial line is configured.
Addressing: primary or secondary
Choose the addressing type:
- Primary — address the meter by its primary address (1–250), the simple bus address assigned to the meter.
- Secondary — address the meter by its identity, using the identification number, manufacturer ID, version, and medium. Useful when primary addresses aren’t unique or assigned.
Reading a value
Each M-Bus tag reads one value from the meter:
- Data type — how the value is interpreted (see Data types).
- Index — which value in the meter’s record to read.
- Number of values — for array data types, how many consecutive values to read.
- Polling interval — how often, in milliseconds, THMI reads the value (default 5000).
M-Bus values are read-only, so there is no writable option.