ARRANGEMENT COMPRISING AN INDUCTIVE PROXIMITY SENSOR, AND METHOD IMPLEMENTING SUCH A SENSOR

摘要

The invention relates to an electronic circuit for detecting proximity comprising: an excitation coil for emitting an inductive excitation field toward a target; a first pair of detection coils for obtaining a first differential inductive signal that is modified by means of a transition of the target within said inductive field; an out-of phase second pair of detection coils for obtaining a second differential inductive signal that is modified by means of a transition of said target within the inductive field; a comparator for generating a transition signal when the difference between the first differential signal and the second differential signal reaches a threshold value; a stationary target, in a ferromagnetic or conductive material, for creating an offset to the signals at the outlet of the coil pairs, said offset to be decreased during the presence of a movable target within the same type of material or increased during the presence of a movable target within another type of material; and a comparator for detecting the offset level so as to deduce therefrom the presence or absence of a target in front of the sensor.