M-Bus Communication Driver is intended for data connection between Reliance's runtime software and devices communicating via the M-Bus (Meter Bus) protocol.
Communication with a PLC runs in one of the following ways:
Connection type can be selected in the Reliance development environment in the Project Structure Manager (connecting a device).
The communication driver is a DLL loaded into memory by the Reliance 4 Driver Server program which can be launched either as a Windows service at Windows startup or as a standard application at the start of a visualization project. Information required to make a connection with the devices is read from the visualization project. After reading this information, communication to the devices is activated.
A connection is established by sending the SND_NKE communication packet. This packet is transmitted even if the connection is cut off. A successful connection is followed by further communication packets. If the connection is not made, the communication driver sends the SND_NKE packet repeatedly at a specified interval.
Reading the data runs periodically or is based on a one-shot request of Reliance's runtime software. This is accomplished by sending the SND_UD2 communication packet. When reading periodically, the communication packet is sent regularly according to the update interval set for individual tags.
The loss of connection is detected if the communication driver doesn't receive a valid response Nx consecutively (N represents the maximum number of failed communications). This parameter can be adjusted.
The communication driver is able to read most devices complying with the M-Bus communication protocol standard. Besides, the communication driver has been tested with these devices:
Heat meters: Siemens UH50, Kamstrup Multical 401, Sensonic 95, Sensonic Plus, Combimeter II
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