The Siemens 7KT1668 combines direct 80 A connection with M-Bus communication and MID certification in the PAC1600 platform. It is purpose-built for building automation systems where meters daisy-chain on an M-Bus network and the readings carry billing weight — tenant sub-metering, cost centre allocation, and energy performance contracts.

Why choose M-Bus for energy meter networking?

M-Bus (Meter-Bus, EN 13757) is the European standard for meter reading networks. It supports up to 250 meters on a single two-wire bus with cable runs up to several kilometres at low baud rates. The bus carries both power and data — meters are bus-powered for the communication interface while the measurement circuit is self-powered from the mains voltage. M-Bus is the natural choice for building automation systems using standards like BACnet or KNX with M-Bus gateways, and for utility-style centralized meter reading in multi-tenant buildings.

When do I need MID certification on an M-Bus meter?

MID certification is legally required when energy meter readings are used for billing — whether that is tenant invoicing, departmental cost allocation with financial consequences, or energy performance contracts with payment tied to consumption. The 7KT1668 is certified under EN 50470-3 Class B, meeting EU legal metrology requirements. If the M-Bus meter is used purely for operational monitoring (no financial dependency on readings), the non-MID 7KT1667 provides the same M-Bus interface without the certification cost.

Frequently Asked Questions

How many 7KT1668 meters can I put on one M-Bus segment?

Up to 250 meters per M-Bus master (level converter), limited by the master's supply capacity — each meter draws approximately one standard M-Bus load (1.5 mA / 1 unit load). In practice, large installations segment the bus by floor or distribution zone using multiple M-Bus masters, all feeding into the central building management system.

What baud rates does the 7KT1668 M-Bus interface support?

The M-Bus interface supports standard baud rates from 300 to 9600 baud, with 2400 baud being the typical default for M-Bus energy meters. The baud rate is configurable via the primary or secondary addressing mechanism.