Photo electric proximity switches or sensors are primarily used when the object to be sensed is metallic or non metallic. Photo electric sensors are three different types:-
- Diffused type photo electric proximity switch.
- Through beam type proximity switch.
- Retro-refractive type proximity switch.
These type of proximity switches contain an emitter and a receiver in one unit.
When the emitter emits the infrared signal which is reflected from the surface of the object to be detected and is ultimately received by the receiver. This will change the output stage.
Through beam type
These type of proximity switches contain separate emitter and receiver, when emitter emits the infrared signal which is continuously received by the receiver and when an object comes in between the emitter and receiver, the signal breaks and thus change the output signal.
3 retro-reflective type
These type of proximity switches containing emitter and receiver in one unit and a reflector is used to reflect the zero diffused beam. When an object comes in between these two the beam is broken and the output will changed its signal
Photo electric proximity switches are used to counting on conveyor belts, webtewar monitoring, sensing the end of a roll etc.