RLK31 Diffuse Block Style AC/DC Photoelectric Sensors The RLK31 range of diffuse photoelectric sensors from Pepperl + Fuchs offers a compact sensor suitable for factory automation applications within industrial environments. Diffuse sensors work when an object moves within the sensing range by using light from the emitter which will strike the target object within range which will then be reflected directly into the receiver unit and activate the sensor. Diffuse sensors are used in part presence, error proofing, fill, product height and lid presence applications. Operating voltage AC / DC Highly visible LED Relay output Compact and stable housing Protection class II