Sensor fit and deployment context
The SICK WL18-2P132 is a photoelectric retro-reflective sensor with a 0 to 7 m sensing range, meaning it detects objects that break a light beam returned by a separate reflector — common for presence detection on conveyors, packaging lines, and material handling gates where the target is opaque and the mounting distance is under 7 m. Rated IP65, the rectangular ABS housing tolerates dust ingress and hose-directed water spray, so it can be deployed on dry indoor lines or covered outdoor transfer stations without a secondary enclosure. The 500 µs response time suits moderate-speed applications. For high-speed counting, a faster sensor would be the safer call.
Electrical and output detail
Operates on 10 to 30 V DC with ripple under 5 V; the PNP switching output (sourcing) is standard for PLC input cards common in European and North American panels — verify your input module sinks current before wiring. Light/dark switching is selectable via the potentiometer, so the same sensor can be set to output when the beam is made (light-on) or broken (dark-on) without changing the wiring — useful when a machine's logic polarity differs between zones.
Mechanical integration
The rectangular housing measures 17 x 75 x 32.5 mm (W x H x D) and terminates in a 2 m PVC cable — no separate connector or pigtail to source, but the fixed cable means the sensor is permanently wired into the junction box or cable gland. PMMA optics material is standard for this class — adequate for dry indoor environments but not rated for chemical washdown or abrasive dust; if your line uses aggressive solvents, consider a glass-optics variant.