Retroreflective Photoelectric Sensor Setup With the “Retroreflective” sensor, it needs a reflector to work. Use a straight edge to line up and mount the sensor and the reflector, so they are straight across the conveyor belt from each other. Adjust the sensor if needed and tighten everything down to lock the sensor and reflector in place. To check alignment, block and unblock the sensor with your hand to make sure the sensor indicator light turns on and off. The “Retroreflective” photoelectric s