When to Use Wireless M-Bus and When Not to Use Wireless M-Bus

What IoT Sensors Can Learn from Automatic Meter Reading

Wireless M-Bus(wMBus) was first designed to meet the requirements for the automatic reading of water and gas meters, which require only a low data rate.

However, as we enter the Internet of Things (IoT), network designers are realizing that many industrial and commercial sensing applications also have low data rate requirements…as well as the requirements for long battery life, long wireless range, low-cost, and easy-to-install RF modules.

1) How difficult is it to run wires to sensors?

Running electricity and data wires to sensors in previously “unwired” locations can easily cost more than the wireless sensor network (WSN) being installed.

Battery operation is the logical alternative, if battery lifetime is sufficiently long. There are now tens of millions of wMBus modules for the automatic meter reading (AMR) of utility meters (Smart Meters) literally locked away in difficult-to-reach locations (e.g., basements, sheds, etc.).

Obviously, long battery life was “top-of-mind” for the creators of the wMBus standard EN 13757. As a result, typical battery life for wMBus modules is 15+ years.

2) How long is your wireless range?

Wireless M-Bus has impressive RF range, even over radio-challenged environments.

We’ve developed an entire Application Note entitled “AN021: RF Modules Range Calculations and Test.” We give wireless range-calculating formulas and then provide three case studies that test their calculations against actual RF measurements.

To simplify the results of the three case studies:

  • A 6-story mixed-use building with an “n” index of 5 (towards the upper range of difficulty for “Different indoor environments over several floors”). The 868 MHz transmitter was placed on the first floor, close to a steel elevator. An off-the-shelf Development Kit including the radio module and antennas were used. Packets were sent every two seconds; 100 of 100 packets were successfully received, while the measured RSSI level nicely matched the calculated RSSI for the most remote (6th floor) location.
  • Free line-of-sight (LoS), from hilltop to hilltop in Norway: 8.3 km wireless range proven, with a theoretical range 32 times longer than that.
  • Downtown Oslo: 3.5 km range using two off-the-shelf antennas mounted on rooftops with a standard Radiocrafts 169 MHz Development Kit for the Wireless M-Bus module. Using low-cost components, you could expand this installation into a simple 169 MHz star network covering a wireless circular range of 40 km2 of the downtown.

3) What are some examples of good use of Wireless M-Bus in Commercial/Industrial Sensing?

  • Energy-Efficient Street Lighting
  • Repositioning Arena Lighting
  • Retrofitting Sensors for HVAC
  • Retrofitting Buildings for Energy Management
  • Retrofit Lighting for Buildings
  • Automated Control of Blinds & Shutters
  • Industrial Alarm Systems
  • Wireless Data Loggers
  • Remote Industrial Controls
  • Agricultural Sensors & Irrigation
  • Occupancy Sensing: Car Parking Systems
  • Optimized Collection for Waste Management
  • Asset Tracking in Warehouses & Transportation
  • Vehicle Traffic Monitoring

…and many other applications requiring highly robust RF communications in radio-hostile areas.

When is wMBus Not Appropriate?

  • When pre-existing electricity and data lines run to all sensor locations
  • When high data rates are required, e.g., for streaming audio/video. WiFi or Bluetooth may be more appropriate for these high data rate wireless applications.

Is wMBus right for your industrial/commercial sensing application?

Contact our wMBus experts: they’ll walk you through the wireless module selection process.