The Siemens 7KT1667 is the non-MID M-Bus variant of the PAC1600 series with direct 80 A connection. It delivers active, reactive, and apparent energy readings over an M-Bus network to a central building management system — the right choice when network-based meter reading is the goal and billing certification is not required.

M-Bus for centralized meter reading — how does it work in practice?

Each 7KT1667 connects to a two-wire M-Bus loop back to an M-Bus master (level converter). The master polls each meter by its primary or secondary address, and the meter responds with energy registers, instantaneous values, and status information. The master typically connects via RS-232 or USB to a building controller, data logger, or edge gateway. From there, data flows into the BMS, energy management software, or cloud platform. The bus topology — daisy-chain from meter to meter — dramatically reduces cabling compared to point-to-point wiring.

Direct 80 A — what are the practical limits?

The 80 A rating is the maximum continuous current per phase. In practice, most three-phase circuits feeding distribution boards, HVAC equipment, or machine groups fall well within this range. The meter connects directly — no external CTs to source, mount, or wire. Conductor size is up to 25 mm² at the screw terminals. If your load is near or above 80 A, step up to the CT-connected 5 A M-Bus variant (7KT1663 or 7KT1664) paired with appropriately rated CTs.

Frequently Asked Questions

What is the difference between primary and secondary M-Bus addressing?

Primary addressing uses a simple 0–250 device address set during commissioning — easy to work with but can cause conflicts when meters from different batches are mixed. Secondary addressing uses the meter's unique factory-programmed 8-digit ID, eliminating conflicts entirely. The 7KT1667 supports both methods, selectable via configuration.

Does the M-Bus interface need a separate power supply?

The M-Bus communication circuit draws power from the bus itself (bus-powered), while the measurement circuit is self-powered from the measured mains voltage. No separate auxiliary supply is needed — only the two-wire M-Bus connection and the three-phase voltage connections.