M-Bus is a wired communication technology used for remote reading of, for example, meters for electricity, water, heat, and temperature.
The supply of various M-Bus meters and equipment is very large, and because the communication protocol and the electrical interface are regulated by an EN standard, equipment from different manufacturers can easily be mixed into customized systems. M-Bus can also be used for controlling and monitoring of processes.
Standard and compatibility
The M-Bus standard defines how communication should work from the electrical level all the way up to including how the actual data is formatted. This means that all M-Bus compliant equipment works well together and that there is no extra product specific information required to interpret or operate M-Bus equipment from a protocol perspective.
Being based on wired communication, its main advantage is the reliability. Unlike radio solutions that always are exposed to changing environments, being affected by other devices that uses the same spectrum and must penetrate changing physical environment, wired solutions are unaffected as long as the wire remains intact.
Bandwidth is limited but systems have excellent robustness against electrical disturbances, caused by e.g. lightning strikes, while at the same time allowing cable lengths up to several km using a standard 2 wire cable.
End devices, such as meters, are called slaves in M-Bus terminology. They are powered by an M-Bus master, typically a separate product or built into a more advanced gateway product. While this design allows meters to only need to rely on the M-Bus cable for both communication and power, it makes the collecting device unsuitable for battery power.
Both Wired and Wireless M-Bus supports
- Two-way communication, but systems are, for technical reasons, most often thought of as “one way”, from the meter/sensor to a receiving system.
- Encrypted meter/sensor data
Wired M-Bus is still a very good and robust solution for applications using simpler meters/sensors and where the cost of cabling is acceptable. The latter is often a critical point making it more popular for e.g. new buildings rather than retrofit projects.