Patent attributes
The present invention provides a proximity switch, which can detect whether a detected object containing multiple metals exists in a specific range. The induction type proximity switch includes: an oscillation switch of which the amplitude is attenuated due to the proximity of the detected object containing metal, so as to detect the excessive proximity of the detected object; a detection circuit for detecting the amplitude of a high frequency generated by the oscillation of the oscillation circuit; an operation and comparison part for comparing the detected amplitude of the high frequency with the threshold set for the amplitude, i.e., a boundary as the excessive proximity, and outputting a detection signal of the excessive proximity when the detected amplitude is under the threshold; and a threshold setting part, for selecting a threshold corresponding to a designated metal type according to the designation on the metal type from the outside.
