The Siemens 3RG7400-0AB00 is a SIMATIC PXO310 K21 diffuse-mode photoelectric sensor in a compact 31x20x12 mm housing. It operates on DC 10-30V with a PNP light-on output rated to 150 mA, and a sensing range of 50 cm. The 2-meter PUR cable (3x0.14 mm²) and IP68 rating make it suitable for washdown or dusty environments.
What the ratings mean for fit
The 50 cm sensing range is the rated detection distance for a standard white card (90% reflectance); actual range drops with darker targets. The PNP light-on output means the transistor switches high when the target is detected — verify your PLC input type (sourcing vs sinking) before wiring. The 150 mA continuous output can drive a small relay or PLC input directly, but not a contactor coil without an interposing relay. The 2 m PUR cable is oil-resistant and flexible down to -25°C, but the 0.14 mm² conductors limit the cable run to about 10 m at 24 VDC without voltage drop compensation.