The D4SL-N2FFA-D is a safety door electromagnetic lock switch from Omron — it physically locks a guard door closed until a 24VDC signal releases the solenoid, and it reports door and lock status through built-in contacts. The mechanical lock / 24VDC solenoid release (code A) means the lock holds the door shut even if power is lost; you need to energize the solenoid to unlock it. That's the fail-safe behavior you want on a guard door: if power drops, the door stays locked. On the switching side, the AC-15 rating of 5A at 120V AC covers pilot-duty loads like contactor coils or indicator lamps in a control circuit. The DC-13 rating of 22A at 125V DC handles DC solenoids or electromagnetic brakes — that's a beefy DC rating for a safety switch, so it can switch a large solenoid directly without an intermediate relay.
Where you'd use it
This class of switch goes on hinged or sliding guard doors on machinery where you need to prevent access until the hazardous motion has stopped. The 2NC/1NO + 2NC contact configuration gives you two independent NC channels for the safety circuit (redundant, so you can wire to a safety relay or safety PLC) plus an NO signal for a status lamp or PLC input.
Installation details
The conduit entry is G1/2 (code 2), so it accepts standard metric or PG cable glands. The head and release key are resin (code F) — non-corrosive, non-sparking, fine for most industrial environments. The 24VDC orange LED indicator (code D) gives you a quick visual on solenoid power without a multimeter.