Digital Hall sensor with timed interrupter for use e.g. in thread or filament industries

摘要

A digital sensor (S) with a Hall element (H) uses the magnetic field (M) to determine the distance of a body. A Schmitt trigger (T) for sampling the output signal (Y) at predetermined time intervals in connected to a pulse monitor (MP). A timed interrupter (U) for the alternate in and out switching of the sensor is installed between the Hall element and the earth or between the Hall element and the voltage source (V) and is linked to the pulse monitor through a resistor (R). The pulse frequency of the interrupter thus determines the sampling frequency and ensures that the output signal (Y) can be sampled only when the sensor is switched in. This precision in the sensor switching eliminates the inaccuracies which may be caused by hysteresis.