The SICK UM18-211161101 is an ultrasonic proximity sensor from the UM18 series, delivering a PNP normally-open output over a 30 to 250 mm sensing window. Switching frequency sits at 25 Hz — fast enough for discrete object detection on a moderate-speed conveyor or fill-level check, but not for high-speed counting. The M12 4-pin connector mates to standard industrial quick-disconnect cabling; no pigtail to dress. Housing is plastic PBT with IP65/IP67 sealing, so it handles washdown and dusty environments without a secondary enclosure. Operating range from -25 to 70 °C covers most indoor plant-floor conditions. Supply voltage is 10 to 30 VDC — common 24 V nominal rail works fine.
Sensing range and switching speed
The 250 mm maximum sensing distance (with a 30 mm minimum blind zone) means this sensor can detect targets from nearly contact out to about 10 inches. The 25 Hz switching rate translates to a response time around 40 ms — adequate for detecting parts on a line running at moderate speed, but too slow for fast-indexing pick-and-place. For a longer reach or slower update, the UM18-212161101 sibling extends to 350 mm but drops to 12 Hz.