PRODUCTS LIST
A high frequency oscillation type proximity switch prevents mutual interference when it is mounted adjacent to other proximity switches. The switch includes a comparator having a threshold value at a level higher than an object detection level of the oscillation output of the proximity switch. When an output is continuously obtained from the comparator, a beat is generated and the generation of mutual interference is detected. Then, the generation is externally displayed, and mutual interference is alarmed and prevented by changing the oscillation frequency.