Multi-Utility M-Bus Meter Pairing (Gas, Water, Heat) via DLMS Class 74 (M-Bus Setup)

[carlos_mendez]

Aggregating Gas and Water Sub-Meters through Electricity Gateways

Smart electricity meters frequently serve as local data concentrators for nearby Wireless M-Bus (wM-Bus EN 13757-4) gas, water, and heat sub-meters using COSEM Class 74 (M-Bus Client / Setup).

Workflow

1. Install gas/water meter with 868 MHz Wireless M-Bus transmitter (Mode T1 or C1).
2. Electricity meter listens on 868.95 MHz.
3. Pairing is initiated by invoking Method 1 (slave_install) on Class 74 object 0.X.24.0.0.255.
4. The electricity meter captures sub-meter telegrams, decrypts using pre-shared AES-CTR/CBC keys, and maps sub-meter readings into COSEM Class 3 registers (0.X.24.2.1.255 for Gas Volume, 0.X.24.2.2.255 for Water Flow).
5. Utility HES reads all electricity, gas, and water data in a single consolidated DLMS association!

[sarah_jenkins]

Channel assignment rule: The X in 0.X.24.0.0.255 corresponds to the M-Bus channel number ($X = 1$ to $4$ for up to 4 slave sub-meters attached to one electricity gateway).

[elena_rostova]

Battery life consideration: wM-Bus gas meters only transmit every 5 minutes in T1 mode (short 10ms chirp). The electricity gateway receiver remains in continuous listen mode powered by the mains grid.