The Siemens 3RG7401-7GA00 is a SIMATIC PXO320 K21 retro reflective photoelectric sensor with a built-in polarisation filter. It operates on DC 10-30V, switches NPN dark-on at up to 150 mA, and detects reflective targets up to 3 meters away. The 31x20x12 mm housing with an M8 3-pole connector and IP68 rating makes it a candidate for washdown zones or tight machine cavities where a standard barrel sensor won't fit.
The 3 m sensing range is the maximum for a standard white reflector; real-world range drops with dirty or low-gain targets. The polarisation filter rejects specular reflections from shiny objects — useful on wrapped pallets or glossy packages. NPN dark-on output means the load is energised when the light path is broken; verify your PLC input card expects sinking (NPN) logic. The M8 3-pole connector carries power and signal only — no alarm or teach line. IP68 allows submersion, but the M8 mating connector must also be rated for the same ingress level to keep the seal.