Method and device for security monitoring of a passage

摘要

The method involves receiving and storing of reference- bit pattern of a permissible object (10) i.e. vehicle body (14). Occurrence of the object-bit pattern is detected during passage of the object in a protection field (26). The occurrence of the object-bit pattern is compared with the occurrence of the reference- bit pattern. A safety signal is only released by a light grid (16), when the determined occurrence of the object-bit pattern not coincides with the occurrence of the reference- bit pattern. An independent claim is also included for a device for monitoring the protection field utilized for transporting the object.