Proximity switch is a position switch that does not need direct mechanical contact with moving parts. When the object moves to the action distance, the switch can be actuated to drive the load, which can be an intermediate relay or a PLC input point. Proximity switches are divided into inductive proximity switches, capacitive proximity switches and magnetic proximity switches.

The inductive head of the capacitive proximity switch is a circular plate electrode, which forms a distributed capacitance with the ground wire of the oscillating circuit. When the conductor or other medium approaches the induction head, the capacitance increases, which makes the oscillator stop oscillating, and the electrical signal is output through the shaping amplifier. Capacitive proximity switches can detect metals, nonmetals and liquids.

Performance characteristics:

Among all kinds of switches, there is a displacement sensor, which has the ability to sense objects approaching it. Proximity switch uses the sensitive characteristics of displacement sensor to close the object to control the switch on and off. When the object moves close to the switch and approaches a certain distance, the displacement sensor will feel it and the switch will act.

However, the detection distance of different proximity switches is different, and sometimes the detected object is at a certain time interval. Move to the proximity switch one by one, leave one by one, and so on. Different proximity switches have different response capabilities to the detected object, and this response characteristic is called response frequency.