Sensor overview and key ratings
The SICK WTB250-2P2451 is a photoelectric proximity sensor with background suppression from the W250-2 series. It uses a visible red LED light source and provides a PNP switching output, configurable for light-ON or dark-ON operation. The sensing range is rated from 200 mm minimum to 1 m maximum, which means it can reliably detect objects at distances up to one meter while ignoring background surfaces beyond that point — useful for conveyor presence detection or part-in-place verification where the background is a fixed surface. Response time is 3 ms, suitable for moderate-speed lines; for faster applications (sub-millisecond), a laser-based sensor like the WTB9L-3P2461 would be a better fit.
Electrical and mechanical fit
Operating voltage range is 10 V to 30 V, which covers standard 24 VDC control systems. The PNP output sinks up to 100 mA — enough to drive a PLC input directly or a small relay. Termination is via an M12 4-pin connector, a common industrial interface. The 20 mm wide housing fits standard DIN-rail mounting profiles; overall dimensions are 20 mm wide, 65 mm tall, and 43.9 mm deep.