Dark-on means the NPN transistor pulls the output low (sinks current) when the light beam is blocked. With the beam uninterrupted, the output is off (high-impedance). This is standard for fail-safe detection: a broken wire or lost power leaves the output off, which a PLC can interpret as a blocked condition.
Temperature range — indoor automation, not the oven
Rated for -25°C to 55°C ambient. This covers most factory-floor and warehouse environments but does not extend to hot machine enclosures, paint booths, or freezer applications. If the sensor sits near a motor housing or oven wall, check the local ambient temperature at the mounting point — not the room average.
For a BOM freeze or long-term supply plan, this part is currently stable; no need to chase an alternate yet.
