Part identity and function
The Omron F3SJ-B1985N25 is a Type 4 safety light curtain from the F3SJ-B series, designed for hand protection with a 25 mm detection capability. It projects 98 beams at a 20 mm pitch to create a 1985 mm protective height, covering the full reach zone for hand/arm entry detection per IEC 61496.
What the ratings mean for fit
The 25 mm detection capability means this curtain catches a hand or finger reaching into the hazard zone — it is a hand-protection class device, not a finger-protection (14 mm) or body-presence (40 mm+) unit. The 20 mm beam pitch and 98 beams give you a 1985 mm guarded height, so it covers a typical standing operator's reach from waist to above the shoulder. The 0.2 m to 7.0 m operating range lets you mount the emitter and receiver up to 7 m apart, which covers most machine access openings without needing a secondary curtain.
Deployment context
Rated IP65, the sensor bodies and optics withstand washdown and dust ingress — suitable for food-and-beverage lines, packaging machinery, and other wet-area guarding. The 24 VDC supply is standard for safety circuits; plan for a dedicated safety-rated power supply or a PNOZ-style safety relay to handle the output switching. Blanking and muting functions are built in, so you can configure fixed or floating blanking to ignore a workpiece or fixture passing through the field without tripping the machine.