Photoelectric Sensor: All you need to know

Thanks to advancing technology, our lives have become so much easier and simpler. Can you imagine life without electricity, the internet, or your phone? One such technological innovation that has revolutionised a number of industries and improved safety is the sensor. There are different kinds of sensors used for performing a myriad of functions, and one of the most important ones is a photoelectric sensor.

In this article, we will discuss everything about photoelectric sensors, from what they are and how they work to the different types of photoelectric sensors and where you can buy them.

What is a Photoelectric Sensor?

A photoelectric sensor is a sensor that detects the presence as well as the distance of an object with the help of light, hence the name.

A photoelectric sensor consists of an emitter that emits either visible or infrared light beam, a receiver that receives the light beam, and in some kinds of photoelectric sensors, a reflector that reflects the light beam towards the receiver.

The emitter in the photoelectric sensor emits a light beam, which, when received back by the receiver, 'reads' the light to detect the presence or the distance of any object present in its path. The reading is then converted into human-readable data and is given as output.

Largely used in industrial manufacturing, photoelectric sensors are extremely effective in detecting the presence, and absence, as well as for measuring the distance of an object. Photoelectric sensors are an integral part of automation since they offer quick results without the need for touching the object physically.

Types of Photoelectric Sensors

Some of the major industries that use photoelectric sensors include automotive, food and beverage, and pharmaceutical. Depending on the kind of work, different kinds of photoelectric sensors are used.

Based on how the photoelectric sensors operate, they can be divided into three types and they are reflective sensor, thru-beam sensor, and retroreflective sensor.

Given below are simple and short descriptions of how each different type works.

1. Diffuse-reflective sensor

In this type of photoelectric sensor, the emitter and the receiver of the light beam are housed within the same box. The light is emitted from the emitter and is received back by the receiver. The received light beam is then read, and if there has been any object detected on the pathway, that is given in the output along with the distance of the object from the emitter/receiver.

2. Thru-beam sensor

A thru-beam photoelectric sensor is slightly different from the reflective sensor. The emitter and the receiver in a thru-beam photoelectric sensor are not housed within the same unit. Also known as the opposed mode, the emitter emits a light beam that is caught by the receiver placed somewhere else. If an obstruction is detected in the light's pathway, it is read, and the distance is given as output by the sensor.

3. Retroreflective sensor

In this third type of photoelectric sensor, there are three parts instead of two. Along with an emitter and a receiver, there is also a reflector. The light beam emitted from the emitter is aimed at the reflector, which then reflects the light beam back to the receiver. The emitter and the receiver are contained within the same unit. However, the reflector is placed elsewhere. When the light travels to the reflector from the emitter and back to the receiver, any obstructions in the pathway are recorded, and the distance is measured. The output is then displayed as a readable numerical value.

What is the output of photoelectric sensor?

The output of a photoelectric sensor can be of two types, namely digital and analogue. Digital outputs can be either on or off and are typically known as sinking outputs (NPN) or three-wire sourcing outputs (PNP). The only exception to this is the relay output that usually comes with an isolated or dry contact that requires one pole to be voltage driven.

Analogue outputs, on the other hand, are dynamic and can provide continuous readings in either voltage (0-10 volts) or current (4-20 mA). While voltage outputs have more interface options and can be easily integrated into control systems, they also have the disadvantage of not running more than 50 feet. Current outputs, on the flip side, can run longer distances without the problem of electrical noises.

Some advanced photoelectric sensors can also provide network communication or outputs in serial for higher-level devices.

Schneider Electric EShop for best photoelectric sensors

All three kinds of photoelectric sensors each have different advantages and disadvantages and are used for different purposes. However, regardless of the kind of photoelectric sensor you are looking for, if you want the best quality, look no farther than Schneider Electric eShop. Featuring different kinds of photoelectric sensors and electronic sensors, you will surely find the kind you are looking for at the Schneider Electric eShop.

In fact, the eShop is home to numerous other electrical devices and appliances. The Schneider Electric eShop is a one-stop destination for all your electrical needs. Visit the website, browse through the listed products, and buy from anywhere at affordable prices.