A photoelectric sensor is used to detect the presence (or absence) of an object, or for measuring the distance between a point and an object. It uses visible red light or infrared light from a transmitter and also has a photoelectric receiver. A photoelectric sensor becomes a popular choice in automation since they provide quick and reliable results without having to physically touch the object.Types of Photoelectric Sensors.
Photoelectric sensors come in different housing styles, sizes, and different working styles. There are three main types of photoelectric sensors:
1. Diffuse type photoelectric sensors
A light beam is transmitted in the direction of the object in question. The light is reflected from the object which is received by the receiver of the sensor confirming the presence of the object. The amount of light received is used by the sensor to measure the distance to the object.
2. Through-beam type photoelectric sensors
A light beam is transmitted from the transmitter on to a receiver while the object of interest is placed between the two. The object interrupts the light and changes the amount of light that falls on the receiver. This is used for sensing the object.
3. Retro-reflective type photoelectric sensors
A light beam from the transmitter falls on to a reflector. The reflector reflects back the light on to the receiver. The object of interest falls between the transmitter and the reflector and interrupts the light beam.
Depending on the requirement, the photoelectric sensor is selected. More sophisticated sensors that are aimed at higher accuracy come with the ability to suppress the background making it possible for them to precisely detect objects.
Applications of Photoelectric Sensors across various Industries.
Photoelectric sensors are widely used across many industries. Some of the industries are as listed below.
Food & Beverage Industry:
Manufacturing and packaging lines in the food and beverage industries also use photoelectric sensors. For example, a plant to cap bottles must be equipped with correctly aligning and orienting each bottle cap. If there are any mistakes in the positioning, the photoelectric sensors can help to detect them to allow for the smooth running of the plant.
When the body of an automobile is built, each component needs to travel down the production line with reliable consistency. Each part needs to slow down and stop in front of the relevant station with perfect timing so that it can be welded or otherwise processed without any error. Photoelectric sensors can detect when the relevant station is near so that the line can stop and the component can be processed.
Photoelectric sensors used in the automotive industry have high precision that makes it possible for them to give accurate results even while operating around various objects with glossy surfaces.
For big machines that need to be operated in perfect synchronization, photoelectric sensors can provide a good level of reliability. In such cases, there is no room for mistake and photoelectric sensors can help to make placement and removal of machine components efficiently.
Doors & Gates:
Automatic doors and gates, for example on buses, trains, elevators, garages, etc. need to have reliable sensing technology so that they open and close at correct times. The entire area in front of the door needs to be under the sensing area for the automated doors to work properly. Photoelectric sensors coupled with infrared scanners can detect approaching people or vehicles.
In storage facilities that have complete or semi-automation, photoelectric sensors make it possible to efficiently track objects in storage, help with automating the storing and stacking of goods, and helps maintain inventories.
Pharmaceutical industry applications such as packaging of medicines also use photoelectric sensors. During packaging, sensors can be used to avoid discrepancies such as empty packaging due to medicine tablets not being present on the line, etc.
Photoelectric sensors are evolving with the rise in demand and accurate, efficient sensors are available that can be used for various purposes. With a sensing range of up to 40mm, the Photoelectric Sensor range from Bulgin provides efficient sensing. They have a high IP rating making it ideal for them to be used in harsh conditions, too.