M-bus Basics: Guide to M-bus master solutions

What is M-Bus?

M-Bus (Meter-Bus) is a bus system used for the remote reading of gas, water, heat or electricity, or other types of consumption meters. It also supports various sensors and actuators. This is a cost-optimized bus for the transfer of energy consumption data, since it is made for communication on only two wires. There is also a radio variant of M-Bus, called Wireless M-bus.

M-bus is European standard (EN 13757-2 physical and link layer, EN 13757-3 application layer). Wireless M-Bus is also specified in EN 13757-4. By being a standardized interface, it is easy to implement it into the projects, since it is not set to specific manufacturers.

There is also an association made for additional level of standardization, that gathers manufacturers that use M-Bus as a communication system in their products.

Where can we use M-bus protocol?

M-bus can be used in the industry, but also, it’s convenient to be used in private households. By the standard, M-bus master can read up to 250 slave devices.

They can be heat meters, water, electrical, or gas meters. You can also use M-bus in applications like alarm systems, flexible illumination installations, heating control, etc. It can monitor different consumption meters, and it can monitor any leakage.

Why choose M-bus?

With energy monitoring, you can find the ways for optimization. And with one of the best relations when it comes to costing and performance, M-bus is a great choice, when you need remote readout.

One of the biggest advantages with M-bus are these:

• You can read all the data remotely, electronically. For example, if you need to monitor heat consumption, you don’t need to go to the site for that.
• It is a very simple protocol – it uses only two wires, and it uses power supply from the users which are connected to the wire.
• Reading errors are minimal. Also, reading is very fast. Further processing is very easy, since the data you receive is presented in machine readable form.
• There are no any special cables – you can use telephone cable. With that one cable, which connects to a building controller, you can attach all the meters in the housing. But, all the meters are still individually addressable! This way you can have control over each consumption meter, while using only one connection cable.

Decode M-bus master solution

Decode has developed different M-bus devices for smart metering. With our MM20 solutions, we provide efficient automatic reading of the energy consumption, anytime and anywhere.

The MM20 device series represent the universal solution for direct or remote readings of the energy consumption on smart meters. They support European M-Bus and OMS standards. They can support up to 20 slave devices, but by connecting them in series, they can support maximum of 250 slaves, as defined by the standard.

Our goal was to provide complete solution and support. So, with M-bus hardware products, we have also developed a software for PC, called M-bus master. It is available for free! And, it is available both for Windows and Linux OS.

We have developed all our products with a great attention to detail, and with safety in mind. MM20 product line has a short circuit protection of M-Bus line and a galvanic isolation for up to 1kV DC. Devices are prepared for 35mm DIN rail mounting and fully adjusted for industrial communications, automation processes and telemetry.

You can easily integrate the products into other remote reading and collection systems without any additional efforts, as they are based on standard protocols and ports. With the mounting option for a DIN rail, integration into already existing automation cabinets is easy.

With our M-bus solutions, you can choose the connection type. It can be by direct connection to the PC, or remotely via Internet or GSM/GPRS connection. Therefore, there are versions with RS232, RS485, Ethernet and USB, and with GSM connection.

M-bus master with serial or Ethernet

MM20-24 is M-bus master converter that enables transparent conversion of serial and Ethernet interfaces into M-Bus interface. As other MM20 products, it supports up to 20 M-Bus slave devices.

There are two versions, one only with the serial interface, and another, with the serial and Ethernet interface.

There is galvanic isolation of Ethernet line, and also short circuit protection of M-Bus line. You can setup all Ethernet parameters through the web interface, which makes it easy to configure and monitor.

You can find more information about this product here.

M-bus master with GSM connection

Our clients’ top choice is MM20-GSM device. It’s M-Bus master device that provides transparent and simultaneous readout of M-Bus slave devices and communication with devices on RS-485 line over GSM network. 

It can read up to 20 slaves, and it uses GPRS communication with control system. Like the other products we produce, it has short circuit protection and galvanic isolation up to 1kV DC.

An extra feature that makes this product even more attractive is that you can do remote control of the logic controllers, intelligent pumps and similar devices which use the Modbus TCP or some other protocol, by connecting them to an additional RS-485 port.

RS-485 port can be configured to convert Modbus TCP to Modbus RTU protocol. You can do local device setup via RS232 interface, or remote device setup over SMS messages or telnet service, which makes the installation pretty easy. Also, there are LED indications that show device status and can be used for complete device state diagnostic.

We also have two versions of this module. MM20-GSM DC supports voltages 9-30V DC, and MM20-GSM AC voltages 230V AC.

You can read more about this product here.

M-bus master with USB connection

MM20-USB is the product that converts M-Bus to USB interface. MM20-USB is powered from USB port, so you don’t need any additional adapters.

It has galvanic isolation, and also there is a short circuit protection of M-Bus line.

LED indications show power supply presence, data transmit and receive. Data rate and format adjustment is performed according to M-Bus slave device.

It’s easy to set it up, since it has plug&play installation, and also driver for virtual serial port. In combination with a laptop, you can use MM20-USB for local setting, testing and reading of consumption meters, and other devices that communicate according to M-Bus protocol. It is compatible with Windows and Linux OS. This converter functions on M-bus line as standard M-Bus master device, and it can support up to 20 M-Bus slave devices.

You can find more information about it on the product page.

Free Decode software tool – M-Bus Master

No matter which communication method, number of meters or number of locations you choose, you can use M-bus Master for collecting and data processing.

M-bus Master is a free software tool developed by Decode, and it can be used with our MM20 products, for easy monitoring and data processing.

M-Bus Master doesn’t have any limitations on the number of meters. Its average reading speed is around 1500 meters per hour. Reading data is kept in a standard XML file and it can be easily exported to a CSV file suitable for working in Excel or importing into a database.

We have it all!

For smart and easy monitoring of consumption meters, it’s worth considering M-Bus protocol. With Decode M-bus metering solutions, you can have accurate information collected from intelligent electricity, water, gas, heat and cooling energy meters.

Decode already has lots of experience with M-Bus application and many successful projects. With one of our projects, we have managed over 1500 consumption meters.

Along with hardware solution, there is a free software that eases data metering.

If you are interested in implementing our products into your project, you are always free to reach us.