The Siemens 3RG7641-0GB00 is a SIMATIC PXO220 M18S retro-reflective sensor with polarized optics and straight M18×52 housing. It runs on 10-30V DC, outputs NPN light-on at 150 mA, and connects via a 2 m PUR cable (3×0.34 mm²). The IP67 rating means it handles washdown environments — fine for packaging lines or conveyor stations where coolant or dust is present.
The 3 m sensing range is the key number for a retro-reflective setup — that's the distance from sensor to reflector, not total beam path. Polarized optics reject false triggers from shiny targets, so it's a good fit for pallet wrappers or bottle lines where film or foil could fool a non-polarized unit. The NPN output (sinking, light-on) means the load is switched when the beam is made; if your PLC input card expects a sourcing (PNP) signal, you'll need a converter or a different sensor. The 2 m PUR cable is oil-resistant and flexible, rated for flexing in cable carriers if needed.