An important European standard for remote facility management is the Meter bus (M-Bus) protocol. This protocol is mainly used for reading of gas or electricity meters.
The Telegea developers have recently implemented the new M-Bus master software module which adds support for reading meters with this type of wired interface. It is based on the excellent Open Source project libmbus which provides the low level protocol implementation. Therefore the Telegea Smart Hub can now act as M-Bus gateway. It is provided with a configurable data logger for the M-Bus meter data. Or it can pass the meter readings directly to the User Web interface where it can be processed and visualized graphically or as tables for chosen periods.
To connect the Telegea Smart Box with the M-Bus 2-wire bus a hardware level converter is needed to adapt the RS232 serial port interface to the M-Bus standard. These converters are available from several 3rd party vendors. They can be connected to the Telegea Smart Hub using the USB port via a USB/RS232 adapter cable.
While this solution is completely functional and can already be used in the field, we are aiming at a more integrated solution to ease installation and lower the total cost of the hardware devices. Therefore we have developed our own level converter which supports up to 20 M-Bus slaves. It will be available as plug in card for the Telegea Smart Hub or as standalone module (with USB interface). The use as add on module for the RaspberryPi B+ and later revisions is also possible since the mechanical design is compatible.
The design and prototyping of the M-Bus master module is completed and production will start shortly. Here is a preview.