M-Bus Bridge

Serial bridge for meter communication using the M-Bus standard.

Overview

M-Bus (Meter-Bus) is an international standard (EN 13757-2) for fieldbus communication with meter devices. The M-Bus Bridge enables OpenEMS to read data from M-Bus compatible meters such as water meters, gas meters, heat meters, and other utility meters via serial connection.

M-Bus is ideal for: * Reading utility meters (water, gas, heat, electricity) * Remote meter data collection * Utility billing and energy management * Building-level consumption monitoring * Small industrial sites with metered devices

The bridge uses the jMbus library for protocol implementation and RxTx for serial port communication.

Components

Bridge M-Bus

Name: Bridge M-Bus

Factory-PID: Bridge.Mbus

Purpose: Master bridge for M-Bus serial communication with utility and facility meters.

Use Cases: * Reading water meter consumption * Monitoring gas meter usage * Heat meter energy readings * Electricity meter data collection (where available) * Multi-meter installations * Building energy accounting systems

Configuration:

  • id (String): Unique bridge identifier; default: "mbus0"

  • alias (String): Human-readable name; default: same as id

  • enabled (Boolean): Enable/disable this component; default: true

  • portName (String): Serial port device name; default: "/dev/ttyUSB0"

    • Linux examples: /dev/ttyUSB0, /dev/ttyS0, /dev/ttyACM0

    • Windows examples: COM1, COM3

  • baudrate (Integer): Serial communication speed in bps; default: 2400

    • Standard M-Bus rates: 300, 2400, 9600, 19200

Prerequisites

Hardware

  • M-Bus compatible meter with serial interface

  • USB-to-M-Bus adapter or RS-232/RS-485 interface

  • Serial cable or M-Bus cable properly terminated

Software Dependencies

  • jMbus library (included in bundle)

  • RxTx native library for serial port communication

System Configuration

Linux Installation (RxTx Native Library)
# Install RxTx native library
sudo apt-get install librxtx-java

# Typical location: /usr/lib/jni/librxtxSerial.so
# If not found, check: /usr/share/java/rxtx/

# If library not in standard location, copy to /usr/lib:
sudo cp /usr/share/java/rxtx/librxtxSerial.so /usr/lib/
Serial Port Permissions (Linux)
# Add user to dialout group for serial port access
sudo usermod -a -G dialout $USER

# Log out and back in, or use:
newgrp dialout

# Verify permissions
ls -l /dev/ttyUSB0
Windows Installation

  • RxTx should be included with Java installation

  • Verify serial port available in Device Manager

  • Grant OpenEMS process permissions to serial port

Source Code