M-Bus to Modbus with PiiGAB M-Bus 900S

The PiiGAB M-Bus 900S has a built-in function to convert the values from M-Bus meters to Modbus. This works great for sites that lack software/hardware for M-Bus and only have software/hardware for Modbus.

Sites with only a Modbus client may use the PiiGAB M-Bus 900S to read-out the M-Bus meters. The built-in M-Bus driver and the Modbus slave software handle all the conversions between the M-bus meters and the Modbus client. Connect the Modbus client to one of PiiGAB M-Bus 900S’s slave ports by TCP, UDP, RS232 or RS485. The PiiGAB M-Bus 900S will then act as a Modbus slave and can receive Modbus RTU or Modbus TCP requests. When the M-Bus client has received responses from the M-Bus meters, the slave port sends a response back to the Modbus client with the read-out from the M-Bus meters. The other slave ports can be used for M-Bus, QuickPost or M-Bus ASCII clients independently.

The conversion between M-Bus and Modbus is handled via two reference files. These files are configured with the PiiGAB M-Bus Explorer software. The configuration of the reference files are done in the same manner as the M-Bus OPC-server in the PiiGAB M-Bus Explorer. The objects which are specified to be read from the M-Bus meters are tied together with one or several Modbus registers. Both files are then uploaded into the PiiGAB M-Bus 900S via the web interface. The Master port and any free slave port are then tied together to these two reference files in the PiiGAB M-Bus 900S.

Advantages with MBus2Modbus

  • The PiiGAB M-Bus 900S itself converts read-outs between M-Bus meters and a Modbus client.
  • PiiGAB M-Bus Explorer is used for configuration, just as with the M-Bus OPC-server.
  • Scaling of the values is possible.
  • Handles large data types such as INT48, INT64 and BCD12 as well as strings.
  • Handles Modbus RTU or Modbus TCP over TCP, UDP, RS232 or RS485.
  • Parallel reading. The other slave ports in the PiiGAB M-Bus 900S can be used independently.