Glossary for detailled explanation - take your pick:
Sensors with unclocked light source are especially suitable to detect fast operations of up to 10kHz. Disadvantage of these unpulsed light beams is their high sensibility as the receiver cannot distinguish between ambient and transmitted light.
Usable Operating Distance Su
The usable operating distance Su considers additionally to the tolerances of the effective operating distance the tolerances for fluctuations in temperatur and voltage (0,81 Sn ≤ Su ≤ 1,21 Sn)
Usage categories are classified in accordance with EN 60947-5-2: AC12/AC140 for AC sensors; DC12/DC13 for DC sensors