Wireless M-Bus

The M-Bus standard defines the operational parameters of communication, extending from the radio layer to the formatting of the data. This implies, from a protocol perspective, that there is no requirement for additional product-specific information to interpret or operate M-Bus equipment.

Wireless M-Bus works according to the master-slave concept, where the M-Bus master collects and processes data from numerous subordinate units called M-Bus slaves. It creates clear communications channels between the individual devices, which indicates that a wireless M-Bus system can consist of several hundred slaves.

The slaves communicate with the master at the frequencies 868 MHz and 434 MHz. The selected frequencies are license-free, which implies that there are no license fees for data transmission.

All radio technologies that use unlicensed frequency bands may experience interference with other radio devices, but wireless M-Bus offers medium range and ability to penetrate certain objects. Still, close consideration needs to be taken when doing the radio frequency (RF) planning. Repeaters are often needed since some messages may be lost due to poor radio conditions. Messages that are lost are typically considered to be non-recoverable.

Bandwidth is low, but wireless M-Bus devices are well adapted for sending frequent messages of data, while still offering long battery life. The battery life of a single AA-sized cell can last for more than ten years. In contrast to wired M-Bus, wireless M-Bus masters can be battery powered. The condition, to still reach reasonable battery life, is that the active receive time per day, needs to be constrained.

It is important to understand that the practical range of a wireless M-Bus system is affected by the required resolution. Typical for wireless M-Bus slaves, is to transmit data several times per hour. If the receiver requires high reliability, indicating receiving at least one message per hour from each slave, or if one message per day is sufficient, the practical range between the receivers and the slave will be considerable.

Wireless M-Bus supports two-way communication. However, it is often referred to as a one-way communication technology as downlink communication is rarely used.

Wireless M-Bus is a suitable communication solution when cabling is unpractical or too expensive. This could be the case if the system is intended for a retrofit or a larger area such as an industrial building.

Elvaco has been utilizing wireless M-Bus for several years with the purpose of providing an uncomplicated and cost-efficient alternative to wired M-Bus. With our two wireless M-Bus receivers, CMeX50 and CMi-Box, we have developed a professional and powerful solution for managing and controlling up to 800 M-Bus meters. Our range of wireless M-Bus technology is completed by several compatible meters and sensors.

Wireless CO2 sensors

In today’s world, monitoring of air quality has become indispensable. The demand for a CO2 sensor with the ability to provide exact measurements while being energy-and cost-efficient, has increased immensely. Elvaco has therefore extended its selection of wireless sensors with Elvaco Sense 300W. In addition to measuring temperature and humidity, the Elvaco Sense 300W also measures the CO2 level.

An advantageous feature of wireless M-Bus is its impressive scalability. It makes it an ideal communication technology for sensors, as there are often several sensors installed on a limited area. For instance, in an apartment building all sensors in the entire building can communicate with the same gateway.

Except from providing reliable and secure values, the wireless sensors have low power consumption. It makes them the ideal option for applications where long battery life is crucial. Our wireless M-Bus sensors can be operated up to 10 years.