The Siemens 3RG7135-3CD00 is a laser thru-beam sensor receiver from the SIMATIC PXO230 L18 family. It pairs with a separate emitter to form a through-beam detection system, used for presence, position, or counting on automated lines where a clean break of the laser beam signals the target. Rated for a 50 m sensing range, it operates on 10–30 VDC and delivers a PNP light-on output rated to 200 mA. The M12 4-pole connector mates to standard sensor cables, and the IP67 rating allows installation in washdown or dusty environments.
The 50 m range is the maximum clear-air distance between emitter and receiver; real-world range drops with dust, mist, or misalignment. The PNP light-on output means the signal is HIGH when the beam is uninterrupted — standard for most PLC inputs. The 200 mA load capacity drives a small relay or PLC input directly without an interposing module. The M18×75 threaded barrel fits standard mounting brackets and through-hole fixtures. The M12 connector is a common 4-pin A-coded type.