Method for securely detecting and positioning objects and safety device

摘要

The method involves periodically scanning a monitoring area (18) with transmitted light beam. The light reflected at objects is received in field of view. A safety signal is issued when invalid object is detected in monitoring area, and actual amount of signal reflections from the reference target (45) is determined. A target reference signal level is calculated corresponding to minimum degree of reflection of reference target. An error signal is outputted when drop below the target reference signal level is detected during working operation. An independent claim is included for a security device for safe detection and position determination of objects in monitoring area.