What is the principle of the proximity sensor?

When the metal detecting body is close to the sensing area of the sensor, the switch will be able to send out electrical commands rapidly without contact, pressure or spark, and accurately respond to the position and travel of the motion mechanism, even if it is used for general travel control, its positioning accuracy, operating frequency, service life, ease of installation and adjustment, and applicability to harsh environments are not comparable to the general mechanical travel switches. It is widely used in machine tools, metallurgy, chemical, textile and printing industries. In the automatic control system can be used as limit, counting, positioning control and automatic protection link.