M-Bus or Meter-Bus is a European standard (EN 13757-2 physical and link layer, EN 13757-3 application layer) for the remote reading of

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...

, gas or electricity meters. M-Bus is also usable for other types of consumption meters, such as heating systems or water meters. The M-Bus interface is made for communication on two wires, making it cost-effective. A radio variant of M-Bus Wireless M-Bus is also specified in EN 13757-4. The M-Bus was developed to fill the need for a system for the networking and remote reading of utility meters, for example to measure the consumption of gas or water in the home. This bus fulfills the special requirements of remotely powered or battery-driven systems, including consumer utility meters. When interrogated, the meters deliver the data they have collected to a common master, such as a hand-held computer, connected at periodic intervals to read all utility meters of a building. An alternative method of collecting data centrally is to transmit meter readings via a

modem A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by modulating one or more c ...

. Other applications for the M-Bus such as alarm systems, flexible illumination installations, heating control, etc. are suitable.

Relation to the OSI model

Since no bus system was available for the requirements of meter reading, the M-Bus was developed by Horst Ziegler of the

University of Paderborn Paderborn University (german: Universität Paderborn) is one of the fourteen public research universities in the state of North Rhine-Westphalia in Germany. It was founded in 1972 and 20,308 students were enrolled at the university in the winter ...

in cooperation with Texas Instruments Deutschland GmbH and . The concept was based on the

ISO-OSI Reference Model The Open Systems Interconnection model (OSI model) is a conceptual model that 'provides a common basis for the coordination of SOstandards development for the purpose of systems interconnection'. In the OSI reference model, the communications ...

, in order to realize an open system which could use almost any desired protocol. Since the M-Bus is not a network, and therefore does not - among other things - need a transport or session layer, the levels four to six of the OSI model are empty. Therefore, only the physical, the data link, the network and the application layer are provided with functions.

Physical wire and connectors

M-Bus connection is called P1, M-Bus or HAN (Home Area Network) consumer connection. M-Bus uses two-wire telephone cable with maximum length of 350 meters when using nominal transfer speeds 300 and 9600 baud. Lowering the speed up to 1000 meter cable can be used. There is no standardized connector, but RJ11 and RJ12

Modular connector A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets. Modular connectors were originally developed for ...

s are used by meter manufacturers.m-bus.com - Physical layer
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References

rSCADA libmbus
An Open Source M-bus library written in C.
jMBus
M-Bus master Java library at openmuc.org.
Valley.Net.Protocols.MeterBus
An Open Source M-Bus library written in C#.

External links

m-bus.com

the free scada project {{Automation protocols Computer buses EN standards

Relation to the OSI model

Physical wire and connectors

See also

References

External links