What this light curtain is and what it guards
That 25 mm figure means it catches a hand or finger reaching into the hazard zone — it's not for finger-level detection (which would be tighter, typically 14 mm), but it covers the hand-sized intrusion that a machine guard must block under IEC 61496-1. The protective height is 1505 mm, so it spans a vertical opening just over 1.5 metres — think a conveyor infeed, a press access, or a robotic cell entry. With 74 beams at a 20 mm pitch, the curtain is dense enough to leave no gap a hand could slip through.
Where it fits — mounting and environment
Operating range is 0.2 m to 7.0 m, so the emitter and receiver can be mounted 200 mm apart at minimum (for tight spaces) or up to 7 metres across a larger opening. At IP65, the housing and optics are dust-tight and protected against water jets — suitable for washdown areas on food or beverage lines, or anywhere hose-down cleaning is routine. Supply is 24 VDC, standard for safety circuits.
Built-in flexibility — blanking and muting
The F3SJ-B1505N25 includes blanking and muting functions. Blanking lets you optically mask fixed obstructions (like a part fixture) inside the protected zone without disabling the curtain. Muting temporarily suspends the safety output when a workpiece is being fed through — common on palletised lines where the material, not a person, breaks the beam. Both are configurable on the unit itself, no external controller needed.