What this sensor is and where it belongs
The SICK WLA26P-P03 is a photoelectric retro-reflective sensor from the W26 family, rated for a 12 m sensing distance with a visible red LED light source. It needs a reflector mounted opposite — the sensor and reflector are a pair, so if you're replacing a through-beam or proximity unit, the mounting and wiring change. The 500 µs response time is fast enough for counting small parts on a conveyor or detecting objects at line speed, but not for high-speed ejection or singulation. The IP66, IP67, and IP69 ratings mean this sensor handles washdown environments — think food processing, beverage lines, or any area where hot water and chemical cleaners hit the housing. The IP69 rating specifically covers high-pressure, high-temperature spray, so it survives the sanitation cycles that kill lesser sensors out here in the grease. The output is configurable as push-pull, PNP, or NPN, which gives flexibility to match whatever PLC input card or relay interface you already have on the panel. Light-ON or Dark-ON switching is selectable via the teach-in or wiring — no extra adapter needed.
Mounting and wiring reality
The M12 male connector (4-pin) means you pre-wire a female cordset, not hard-wire into the housing. If your existing line uses pigtail sensors with flying leads, you'll need an M12 cordset or an adapter. Operating voltage range is 10 to 30 VDC, so it runs on standard 24 VDC control power without a separate supply. The load current is 50 mA — well within the capacity of most PLC outputs or relay coils.