The SICK WL18-P630 is a photoelectric reflex sensor — a self-contained unit that detects objects by sensing the light returned from a separate reflector, not the target itself. It switches a PNP output in either light-on or dark-on mode, so it can be wired to signal presence (light-on) or absence (dark-on) depending on the application. The 4.5 m sensing range covers moderate-distance detection on a conveyor or through a machine access point. Operates on 10-30 VDC, nominally 24 VDC, and terminates in a 6-pin square plug — a common M18-style footprint that mates to standard field-wireable connectors or pre-molded cables.
The WL12-2P430 is the closest functional sibling — same PNP output, same 10-30 VDC supply, same light/dark switching flexibility. The WL12-2P430 reaches 5 m (vs. 4.5 m for the WL18-P630) and uses a 4-pin M12 connector instead of the 6-pin square plug. If your existing harness is M12, the WL12-2P430 drops in without a connector change; if you need the extra pin for a second output or a teach line, the WL18-P630 is the one.
Deployment context
A reflex sensor like this is typically aimed at a reflector mounted opposite the detection zone — no separate receiver cable to run, just power and signal back to the controller. The 4.5 m range suits it for pallet detection on a conveyor, part-present at a machine load station, or through a small gap in guarding. The 6-pin plug gives you options: power, PNP output, and spare pins for a second output or a remote teach if the application calls for it.