The Omron D4NL-4AFG-B4 is a guard lock safety-door switch — the kind that physically locks a machine guard closed until the solenoid is de-energized and the control circuit confirms the hazardous motion has stopped. It carries two independent contact blocks: one 1NC/1NO slow-action pair plus another 1NC/1NO slow-action pair, giving you four total contacts to wire into the safety chain and the status feedback loop. The solenoid locks the door at 24 VDC; the mechanical release lets an operator or maintenance tech override the lock without power — useful during setup or a jam clear when the solenoid can't be energized. Rated IP67 per EN60947-5-1, so the switch body and the head seal against washdown and dust ingress on a food, beverage, or pharmaceutical line where you hose the machine down between batches. The orange LED indicator (B version) lights across 10 to 115 VAC/VDC — it tells you at a glance whether the solenoid is powered, which is the first thing a technician checks before reaching into the guarded zone.
Operating speed of 0.05 to 0.5 m/s governs how fast the guard can be opened or closed without damaging the switch mechanism — too fast and the slow-action contacts may not engage cleanly; too slow and the door dwells in the unsafe zone longer than the safety circuit expects. The M20 conduit entry (size 4) accepts standard metric gland fittings; plan for that knockout when routing the cable into the enclosure. Rated for 30 operations per minute maximum — that's the mechanical endurance limit. On a high-cycle door (every part pass), you'll need to check whether the cycle rate stays under that ceiling.
Integration notes
The head mounts in four directions — front-side mounting as delivered, but you can rotate it to top, bottom, or side to match the guard geometry and cable exit.