EUCHNER CES-AP-CL2-CH (Multicode) - Manual (Page 7)

Operating Instructions Safety Switch CES-AP-C.2-CH
7
If the safety door with the actuator should settle over time, the actuator can drift
out of the read head operating distance. The device recognizes this and indicates
that the actuator is in the boundary area (function available for V 1.1.2 and higher).
This allows the safety door to be readjusted in time.