What Are Photoelectric Sensors ?

Photoelectric Sensors detect objects, changes in surface conditions, and other items through a variety of optical properties. A Photoelectric Sensor consists primarily of an Emitter for emitting light and a Receiver for receiving light. Intelligent sensors embedded with advanced features enable remote diagnostics, reducing machine downtime and enhancing productivity and reliability.

Types of Photoelectric Sensors

There are three major types of photoelectric sensors: thru-beam, retroreflective, and diffused. Each sensor has its own strengths and can be used in a variety of ways.

Thru-Beam

In thru-beam sensing is also known as opposed mode, and two separate devices are used to make or break a beam. One sensor houses the light emitter while the other houses the receiver. A thru-beam sensor detects objects when an object interrupts the light beam between the two sensors. The advantages of using a thru-beam sensor are that it’s the most accurate type of sensor and has the longest sensing range of the three. 

Retroreflective

In retroreflective sensing, both the light source and the receiving device are found in the same housing. The sensor works in tandem with a reflector. The light emitted from the sensor is aimed at the reflector, which is then sent back to the light receiving element. The sensor detects the presence of an object when the light path is interrupted. When working with clear or transparent products, retroreflective sensors are the best option. 

Diffused

In optical proximity sensing, also known as diffuse, the light source and the receiver are housed in the same device. Diffused sensors detect objects when the light beam, emitted towards the target, is reflected back to the sensor by the target. Diffused sensors are a good automation option, because they are more compact than typical units, as all components are in a single housing.