Proximity switch: Proximity switch, also known as con tactless travel switch, in addition to complete travel control and limit protection, it is also a non-contact detection device, used to detect the size of parts and speed measurement, etc., can also be used for frequency conversion counter, frequency conversion pulse generator, liquid level control and automatic connection of processing programs. It is characterized by reliable operation, long life, low power consumption, high repositioning accuracy, high operating frequency and adaptability to harsh working environment. In various types of switches, a component that has the ability to “sense” objects approaching it. The difference between the three: 1. The proximity switch is a con tactless switch with a long life and is suitable for “passing signal” 2. Limit switch (also called travel switch) is a contact switch, suitable for single-direction position detection because of the contact, the relative life is short. 3, the stroke switch is also known as the limit switch, the stroke switch and the limit switch are position switches, but the stroke switch can detect the stroke and can be used as an input signal to control the circuit at a certain distance. It is different from the limit switch to detect the signal of the limit position and play the role of stopping and protecting.