Detects any target capable of blocking light. Where the target passes between the sensor and a reflector, blocking the beam to cause the receiver to change states. The emitter and receiver are in the same housing.

Sensing Range: 0-12 m

Advantage: Best for conveyors or transparent targets, medium sensing range.
Disadvantage: Requires a reflector, affected by dirt build-up.

Applications: Conveyors, large openings, bottle detection.