The SICK VL18-3P3840 is a cylindrical retro-reflective photoelectric sensor from the V18 series, rated for a sensing distance of 3.7 m with a visible red LED light source. It switches dark-on (output conducts when the light beam is broken), which is the typical configuration for presence detection in material-handling and packaging lines — a broken beam signals an object present. Output is PNP, 100 mA load capacity, with a 2 ms response time. Supply range is 10–30 VDC. The M12 4-pin connector mates to standard quick-disconnect cables, so field replacement takes under a minute — no rewiring at the terminal block. IP67 rating means the housing and optics survive washdown and dusty environments — suitable for food-and-bev lines, conveyor tunnels, or outdoor sorting stations.
Drop-in fit vs. VL18-3P3640
The VL18-3P3640 shares the same 18 mm diameter, 3.7 m range, PNP dark-on output, M12 connector, and IP67 rating. The only dimensional difference is length: 78 mm on the 3640 vs. 75 mm on the 3840. That 3 mm gap is negligible for panel clearance — the sensor body and mounting nut are identical. A panel wired for the 3640 accepts the 3840 without any wiring change or bracket modification.