AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

What Are Photoelectric Sensors?

Photoelectric sensors are devices that may be found in a number of industries and applications, capable of detecting the presence or absence of an object through the use of light. With this basic ability, photoelectric sensors find use in applications ranging from the counting of objects on a production line to the operations of an automatic door. Depending on one’s needs, different sensor subtypes may be procured, common options being through-beam, retroreflective, and diffused variations. In this blog, we will discuss each type in brief detail, allowing you to have a better understanding of their designs and functionalities.

Regardless of the type, most photoelectric sensor options work through the same basic set of principles. Photoelectric sensors will feature an element known as an emitter which serves to emit a beam of light to another element called a receiver. From here, different options may present varying steps following emission. Depending on the sensor, the light may directly travel to the receiver, reflect back to the emitter, etc.

With a through-beam photoelectric sensor, the emitter and receiver are two separate components that are placed apart from one another while being aligned. During standard operations, the emitter will send a beam of light to the receiver which is received as long as no object is present. Once an object blocks the beam of light, the output of the sensor will switch off, resulting in a signal being transferred from the sensor to the PLC. This process enables the device to determine that an object is present in the line of sight of the emitter and receiver at that time. As compared to other options, through-beam photoelectric sensors are known for their high detection range. That being said, they can be more difficult to set up with a separate receiver and emitter that must be aligned, and they are not optimal for clear objects where a light beam may pass through.

With a retroreflective photoelectric sensor, the emitter and receiver are placed in the same assembly. As such, a reflector is positioned in a way that allows the emitter signal to be reflected back to the receiver. The output and continued process is very similar to the through-beam sensor, detecting the presence of an object when the beam is blocked. As the signal needs to transfer farther, retroreflective sensors have a shorter detection range. Despite that, they can be cheaper with a single assembly being used for the emitter and receiver.

Diffuse photoelectric sensors further consolidate parts by having the emitter and receiver placed in a single assembly while also being devoid of a reflector. As such, the object being detected serves as the reflector as the beam bounces off the object and back to the receiver. While this makes things more simplistic, detection is dependent on the object being able to reflect the light beam back to the receiver.

Whether you require through-beam, retroreflective, or diffused photoelectric sensors, look no further than Stacked Aerospace for all your operational needs. Owned and operated by ASAP Semiconductor, we offer customers access to an unrivaled inventory of over 2 billion new, used, obsolete, and hard-to-find parts that trace back to leading manufacturers that we trust. As you explore, take note of any items of interest so that you may submit a Request for Quote form. By offering us information such as your target price and shipping time frame, we can best formulate a solution that meets your needs. Give us a call or email today and see how we can serve as your strategic sourcing partner for all your operational needs!



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