CX-421-P-Z Compact Diffuse Reflective Photoelectric Sensor - 300 mm Sensing Distance - PNP - M8 4 Pin Receptacle

In Part 1 of our photoelectric sensor series we examined thru-beam sensors and why they are the most reliable over long distances. Next on our list are retro-reflective sensors. Unlike thru-beam sensors, which have the emitter and receiver housed in different units, retro-reflective sensors have the emitter and receiver collocated. Once the light is emitted it will travel across the detection zone and bounce off a prismatic retro-reflector. The receiver will then detect that the light has returned. Once the light beam is broken the sensor will indicate that an object is present. What makes retro-reflectors unique is that they will always reflect waves back directly towards the source. This makes alignment easier as the sensor doesn’t need to be perfectly perpendicular to the reflector. What if something shiny passed by and reflected the beam back to the sensor? A standard retro-reflecti