The Siemens 3RG7642-3CD00 is a SIMATIC PXO230 M18S thru-beam sensor receiver — the straight-optics half of a photoelectric pair. It runs on 10-30V DC, outputs PNP light-on at 150 mA, and reaches 6 m through the beam. Housed in a standard M18×65 barrel with an M12 4-pole connector, it's rated IP67 for wet or dusty environments. The surplus light detection mode means the output turns on when the receiver sees the emitter's beam — typical for presence sensing in packaging, conveyor, or material handling lines.
The 6 m sensing range is the maximum clear-air distance between emitter and receiver — real-world range drops with dust, mist, or misalignment, so plan for a 20-30% derating in dirty environments. The 10-30V DC supply is standard for industrial photoelectric sensors; PNP light-on output is compatible with most PLC inputs (sourcing type). The M12 4-pole connector is a common field-replaceable interface — no special cabling needed. IP67 means the housing is sealed against temporary immersion, so it can handle washdowns or outdoor installs as long as the connector is properly mated.