The annular trough type photoelectric switch is actually a type of through-beam photoelectric switch, also known as the U-shaped photoelectric switch. It is an infrared sensing photoelectric product composed of an infrared emitting tube and an infrared receiving tube. The width of the trough determines the strength of the sensing receiving model and the distance of the received signal. It uses light as the medium and receives and converts the infrared light between the light-emitting body and the light-receiving body. Detect the position of the object. The trough-type photoelectric switch is also a contactless type of proximity switch, less restricted by the detected object, and has a long detection distance, capable of long-distance detection (tens of meters). It has high detection accuracy and can detect small objects. It is widely applied. The Rihuan trough type photoelectric models are complete, with stable quality and affordable prices.