The unit is installed between the consumer and the connection to power supply. The effective electrical power that is consumed is displayed digitally in watts. Because the output is determined by a real-time multiplication of current and voltage, the measured result is unrelated to the curve form and provides accurate measured results, even in the case of phase control. The measured value is shown as an analog voltage signal on a 5-pin output port in the front panel. The wattmeter can be connected to the interface module HM 280.01 via the output port.

Determination of unit efficiency in the HM 280 - HM 292 series for the following units:

- HM 285 Piston Pump Demonstrator

- HM 286 Gear Pump Demonstrator

- HM 290 Turbine Demonstrator Supply Module