What this light curtain covers and where it fits
The Omron F3SJ-B1745N25 is a Type 4 safety light curtain from the F3SJ-B series, rated for hand protection with a 25 mm detection capability — that means it catches a hand or finger reaching into the hazard zone, not just a full arm. The 1745 mm protective height and 86 beams at 20 mm pitch give it a tall, dense sensing field suited for guarding large vertical openings like robot cells or palletizer infeed stations. Operating range spans 0.2 m to 7.0 m, so it works in both tight machine-loading areas and wider access points. Supply is 24 VDC, standard for safety circuits in most control panels. The IP65 rating means the emitter and receiver housings are dust-tight and resist water jets — fine for dry assembly lines or occasional washdown, though not for high-pressure or submerged environments. Built-in blanking and muting functions let you program fixed or floating obstructions (like a fixture passing through the field) and bypass the curtain during a defined material-handling cycle. This avoids the need for an external safety controller for simple muting applications.
The 25 mm detection capability is the critical spec: it defines the smallest object the curtain can reliably see. For hand protection per IEC 61496, 25 mm is the standard finger/hand threshold — a 20 mm beam pitch with 86 beams achieves this resolution across the full 1745 mm height. Protective height of 1745 mm covers the vertical zone you need to guard. The actual sensing field extends past the ends of the housing by a small margin, but plan your mounting brackets so the beam array starts and ends at the hazard boundaries. Operating range of 0.2 m to 7.0 m sets the minimum and maximum distance between emitter and receiver. Below 0.2 m the curtain may not synchronize; above 7.0 m the optical margin drops. For longer spans, look at the F3SJ-B high-range variants. The IP65 ingress protection handles dust and splash, so it's safe on assembly lines with coolant mist or light washdown — but not for food-processing high-pressure spray zones.
Because it's an active part, you can expect consistent availability for new installations, replacements, and spares. No need to worry about end-of-life stockpiling or searching surplus channels.