Sick VL18-4P3940 Photoelectric retro-reflective sensor PNP

Industrial detection sensor

The Sick VL18-4P3940 is a cylindrical photoelectric retro-reflective sensor built for industrial automation. Its M18 x 1 threaded housing measures 75 mm in length and carries a radial optical axis. The unit operates on 10 V DC to 30 V DC supply voltage and connects via a male M12, 4-pin connector. A visible red LED emits a 2.8° dispersion angle, producing a 150 mm light spot at 3 m distance.

Automation engineers and machine builders

This sensor suits engineers who need a PNP switching output with selectable light or dark switching via an L/D control cable. The potentiometer allows 270° sensitivity adjustment for precise setup. It is not for applications requiring an NPN output type or a different connector format. Buyers who need a through-beam or diffuse detection principle should look at other models. The IP67 enclosure rating supports harsh environments.

Stable operation under continuous cycling

The sensor delivers a 2 ms response time and a 250 Hz switching frequency for reliable detection on fast production lines. Output current is limited to 100 mA with built-in circuit protection A, B, C and D. Protection class III and an operating range of –25 °C to +70 °C ensure consistent behaviour during extended shifts. The plastic PBT/PC housing and PMMA optics resist industrial wear while maintaining optical clarity.