Retroreflective Sensors, Reflector

Size of Reflector

In the example at left, the target is bigger than the reflector, so all light bouncing back from the reflector is cut off. If you're operating in "dark operate", you get an output when the sensor can not "see" its own light. This situation cannot exist, as shown on the previous slide, if the target is not big enough to block light from the reflector back to the sensor. In the example here, no light can get back to the sensor, which is what you want.

Summary:

Be sure to size your reflector properly for your application. They are available in several sizes.