The sensor is a detection device that can transform the perceived information into an electrical signal output according to a certain law to meet the requirements of signal transmission, processing, storage, display, recording and control.

The inductive proximity switch detects that the object is metal (such as: iron, steel, copper, etc.); The capacitive proximity switch detects any object (such as glass, metal, plastic, water, oil, paper, etc.); Hall-type proximity switches detect objects as magnetic metals (e.g., magnets); The diffuse photoelectric switch detects solid component objects (transparent and opaque objects) of liquid and solid, such as tables, walls, transparent glass, metal plates, etc. The feedback and reflection type photoelectric switch detects that the object (with the help of the reflector) is an opaque object, such as: plastic, metal plate, etc. Through type and channel type photoelectric switch detection object is opaque object, such as: plastic, metal plate, etc. Optical fiber sensors detect transparent and opaque objects; Color label sensor is a sensor that detects color; The light curtain sensor is a sensor that detects the invasion of solid objects and controls the stop of potentially dangerous equipment.