What the 20 mm detection capability means for fit
The Omron F3SJ-A0635P20 is a type-4 safety light curtain from the F3SJ-A series, rated for finger and hand protection with a 20 mm detection capability. That 20 mm figure is the smallest object the curtain reliably catches — anything smaller than that passes through undetected. For a safety application, this means the curtain is sized for hand and finger access into a hazard zone, not for full-body presence detection. The 15 mm beam pitch and 42 beams give it a 635 mm protective height, so it covers a vertical zone just over half a meter tall. The operating range spans 0.2 m to 9.0 m, which covers most machine guarding distances from a press to a conveyor infeed.
Deployment context — where this curtain goes
IP65 rating means the emitter and receiver housings are dust-tight and protected against low-pressure water jets — suitable for washdown environments like food processing lines or machining cells where coolant mist is present. The 24 VDC supply is standard for safety circuits; the curtain draws its power from the control cabinet, not a separate supply. Blanking and muting functions are built in, so you can program fixed or floating blanking zones for workpiece pass-through and mute the curtain during non-hazardous machine cycles without external bypass modules.