The Omron D4A2918N is a limit switch from the D4A series, fitted with a roller lever actuator and a 2CO contact configuration. It switches up to 600 VAC at 1.2 A or 250 VDC at 400 mA, with an insulation voltage of 500 V. The IP67 rating means the switch body and the roller lever mechanism are sealed against dust ingress and temporary immersion — suitable for washdown zones on packaging lines or conveyor transfer stations where coolant spray is present.
Termination is via a 0.5-14 NPT conduit thread — the standard for US industrial enclosures. The 2CO contacts (two form C changeover pairs) give one normally-open and one normally-closed set per pole, which covers both safety-circuit feedback and PLC input in a single device. Wire the common to the supply, the N.O. to the input card, and the N.C. to the safety relay chain. The roller lever actuator provides overtravel and side-approach actuation; mount so the roller contacts the cam face squarely to avoid side-loading the lever pivot.