The SICK WTB27-3S1511 is a photoelectric proximity sensor from the W27-3 series, delivering a 1.6 m sensing range with a change-over contact (CO) output. It uses an infrared LED emitter and switches on light-ON logic, with a 10 ms response time. The housing is 24.6 mm wide, 80.6 mm tall, and 54 mm deep, sealed to IP66 and IP67 for washdown or outdoor placement. Operating voltage spans 20 V to 250 V AC/DC, and the temperature range runs from -40 °C to 60 °C. Termination is via a 2 m cable.
The 1.6 m sensing distance is the maximum reliable detection range against a standard white test target; real-world range drops with darker or less reflective objects. The change-over contact output gives you both normally-open and normally-closed in one package — handy for wiring into a safety circuit or PLC input without an extra relay. The 10 ms response time is typical for relay-output photoelectrics; fine for conveyor presence detection, not for high-speed counting.