Rotation sensor, e.g. for battery-powered water meter

摘要

The rotation sensor has a rotor which comprises at least two sectors of different magnetic characteristics. A circuit is provided for detecting the movement state of the rotor using one or more sensors arranged adjacent to the rotor. The sensors each contain an oscillator circuit which is damped by the sectors of the rotor. The decay time of the oscillation excited by an impulse is dependent on the magnetic characteristics of the sector adjacent to the oscillator circuit. For each signal sequence produced by an impulse excitation of an oscillator circuit, a signal processing circuit produces a DC voltage signal whose level exceeds the input threshold to a microprocessor while the oscillation amplitude is above a certain threshold. The microprocessor is provided for evaluating the signals from the signal processor circuit.