A photoelectric switch is a sensor that uses a photoelectric element as the detection element. It first converts the measured changes into changes in the optical signal, and then uses the photoelectric element to further convert the optical signal into an electrical signal. The photoelectric switch is generally composed of three parts: a light source, an optical path, and a photoelectric element. The photoelectric detection method has the advantages of high accuracy, fast response, non-contact, and multiple measurable parameters. The sensor structure is simple, and the form is flexible and diverse. Therefore, Photoelectric sensors are widely used in detection and control

There are various optical measurement and control systems made from the different principles of the action of light flux on optoelectronic components. According to the output properties of optoelectronic components (optical measurement and control systems), they can be divided into two types: analog optoelectronic sensors and pulse (switch) optoelectronic sensors. Analog optoelectronic switches convert the measured photocurrent into continuously changing photocurrent, It has a single value relationship with the object being measured. Analog photoelectric sensors can be divided into three categories according to the method of being measured (detecting the target object): transmission (absorption) type, diffuse reflection type, and shading type (beam blocking). The so-called transmission type refers to the object being measured being placed in the optical path, and the light energy emitted by the constant light source passes through the object being measured. After some of it is absorbed, the transmitted light is projected onto the photoelectric element; The so-called diffuse reflection type refers to the light emitted by a constant light source projected onto the tested object, which is then reflected from the surface of the tested object and projected onto the photoelectric element; The so-called shading type refers to when a portion of the light flux emitted by the light source is blocked by the measured object's light, causing a change in the light flux projected onto the photoelectric element. The degree of change is related to the position of the measured object in the optical path