Wireless MBus (WMBus)

Remote metering lets utilities monitor, analyse and control the consumption of water, heat and electricity. Wireless M-Bus (WMBus) is a radio standard made for this job: meters send their readings over the air, so nobody has to visit the meter and no communication cable has to be laid. Compared with manual readings or wired meter networks, this is faster, takes less work and avoids reading errors. A gateway or concentrator collects the telegrams of many meters and passes the values on to the systems that store and analyse them, so utilities always have current consumption data.

Wireless M-Bus works in the 868 MHz band. Meters send short radio telegrams at set intervals in S, T or C mode; the telegrams are usually AES-128 encrypted, so only a receiver that holds the meter's key can read the values. The Open Metering System (OMS) specification defines how the values are coded, so meters of different makes can be read by the same gateway.

STG Series gateways sit at the centre of such a network: they receive the telegrams, decrypt and map up to 128 meters (STG154 Lite: 20) and offer the values as Modbus TCP / RTU registers and MQTT messages; they also work as a transparent gateway or as a repeater. Meters heard on the air are listed on the web interface and can be added without typing.