A detailed overview of the types of photoelectric sensors

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Photoelectric sensors feature non-contact operation, fast response, and reliable performance, which is why they are widely used in the field of industrial automation. This time, the focus is on analyzing the types of photoelectric sensors. Photoelectric sensors are classified by housing shape: cylindrical and square. The housing of the photoelectric sensor can now be chosen as round or square depending on the customer’s installation environment; there is no fixed specification for this. Photoelectric sensors are classified by detection method into through-beam, mirror reflection, and diffuse reflection types. Opposition-type photoelectric sensors have the greatest detection range among photoelectric sensors, with ranges that can reach several meters or even over a dozen meters. During installation, a transmitter and a receiver must be installed facing each other. The detection range of mirror-reflection type photoelectric sensors is slightly shorter than that of through-beam sensors, but they are much easier to install compared to those sensors; they can be installed in tight spaces as long as a reflector is used. Their advantage lies in their ability to detect the presence or absence of transparent objects. The detection range of the diffuse reflection photoelectric sensor is not as good as that of the previous two, but its installation method and location are more convenient compared to the former two. Photoelectric sensors are classified by light source: visible red light, invisible infrared light, and lasers. The light source of a photoelectric sensor is selected based on the customer’s requirements as well as the object to be detected and the detection environment. Visible light, red light, and infrared light cause the size of the light spot to change depending on the distance, but lasers do not exhibit this behavior; the size of the laser light spot does not change with distance. Lasers are suitable for detecting the presence or absence of small or micro-sized objects, as well as for applications such as counting and positioning