The Siemens 7KT1654 is the M-Bus MID variant of the PAC1600 single-phase series. It is the go-to meter for multi-tenant buildings where individual apartment or unit consumption is metered, networked over M-Bus, and billed to the tenant — all from a compact 2-module DIN rail device.

M-Bus on a single-phase apartment meter — how does the network work in practice?

Each 7KT1654 in each apartment connects to a single two-wire M-Bus loop that daisy-chains through the building back to an M-Bus master in the electrical riser or building management room. The master polls each meter by its unique secondary address (factory-programmed 8-digit ID), collecting energy registers, instantaneous values, and status. Up to 250 meters can share one M-Bus segment — more than enough for even large residential towers. The M-Bus carries both data and communication power, while the measurement circuit is self-powered from the 230 V mains. The master typically forwards data to the building's BMS, a cloud energy management platform, or a billing service provider via RS-232, USB, or Ethernet.

Why combine M-Bus with MID certification?

M-Bus is the European standard for networked meter reading; MID is the legal requirement for billing. Together they form the standard solution for tenant sub-metering in the EU. The M-Bus network eliminates the need to physically access each apartment for meter reading. The MID certification makes each meter's readings legally valid for invoicing. If your building uses a different building automation protocol (BACnet, KNX), M-Bus gateways are widely available to bridge the meter data into the BMS.

Frequently Asked Questions

How many 7KT1654 meters can share one M-Bus master?

Up to 250 meters per M-Bus segment, limited by the master's supply capacity. Each meter draws approximately one standard M-Bus unit load (1.5 mA). For buildings with more than 250 apartments, use multiple M-Bus masters — one per floor or per riser — all feeding into the central management system.

Can the 7KT1654 measure both import and export energy?

Yes. The meter records both consumed (import) and generated (export) energy in separate registers accessible via M-Bus. This supports apartments with rooftop PV where net metering or separate feed-in tariffs apply — the meter tracks both directions independently.