wM-Bus Meter Reading Software

What it does

wM-Bus Meter Reading Software is a Windows desktop application that reads radiator heat allocators, heat meters, and hot and cold water meters that communicate over wireless M-Bus. These meters broadcast their readings as short radio packets (telegrams) in the 868 MHz band. The software listens to those broadcasts through a USB receiver, decodes them, writes each value against the right flat in the building list and exports the result to Excel. No cable is run to the meter, and the meter is never polled.

Reading is organised by building and billing period. The meter list comes from Excel or a ready-made template; once listening starts, each meter read turns green. The status bar shows total, read, remaining and unlisted counts, elapsed time and progress, so the team sees at a glance which flats are still missing.

How it works

1. The USB receiver is plugged in and its serial (COM) port is selected in the software.
2. The listening mode used by the meters is selected and listening starts.
3. Every broadcast in range is captured. Meters whose serial number matches the building list are written to their row; the rest are counted separately as "unlisted". Since meters in neighbouring buildings can be heard too, this separation matters.
4. Encrypted broadcasts are decrypted with the AES-128 key that belongs to that meter. Keys are stored per meter and can be entered one by one or imported in bulk.
5. When reading is finished, the values are exported to an Excel file filed in a folder named after the building.

Each session is logged hourly per building, with decoded and undecodable telegrams kept apart, so a missing meter can be traced to the mode, the range or the key.

How it differs from the M-Bus reading software

Wired M-Bus (EN 13757-2 and EN 13757-3) is a two-wire line: the reading device asks, the meter answers straight away. Wireless M-Bus is defined in EN 13757-4 and turns this around: the meter transmits on its own schedule and the receiver only listens. In the field this has three consequences:

• The mode has to be right. Meters transmit in different modes. The software supports the C, S and T modes, the T1C mode that listens to T1 and C together, and the C1TFA mode. A meter heard in the wrong mode never appears in the list.
• Patience is needed. Meters in S mode transmit infrequently and can take a long time to appear. On a wired line the answer arrives the moment it is requested.
• Decryption is needed. Most wireless meters encrypt their broadcasts with AES-128. Without the key the meter shows up in the list, but its consumption value cannot be read.

If your meters are connected by a two-wire M-Bus line, the companion M-Bus Meter Reading Software is the right tool.

This software focuses on wireless meter reading itself and works independently of whichever allocation or billing program you use; its output is Excel and what happens next is up to your own process. If you want the reading round written straight into the meter list of EnerjiPay allocation, the field leg of that chain is described on the EnerjiPay RF page.

Technology

The program is written in Python with PyQt6 and is distributed as an installer for Windows 10 and 11. Data is kept in a single-file SQLite database. The software reads meters that transmit using the EN 13757-4 (wireless M-Bus) protocol, independent of brand; encrypted meters require that meter's key. Telegram content is interpreted by 21 meter drivers, and the meter type is recognised automatically from the telegram.

Telegram processing is multi-threaded and interface updates are batched, so the program stays responsive in busy buildings. The licence is tied to the computer and validated with a signed key. At start-up the program checks for a new version and will not use a downloaded installer until its fingerprint has been verified.

Where it is used

Typical uses are reading radiator heat allocators and heat meters in centrally heated buildings, reading hot and cold water meters, and collecting data for periodic heating bill allocation. The reading team places the receiver at a suitable point in the building, completes the round without entering the flats and passes the Excel output on to the allocation process.

Product site

Installation steps, receiver placement, listening modes and entering AES keys are covered in detail in the installation guide on the product site, where the latest version of the software can also be downloaded.