Patent ID: 7741595
Filing Date: 2010-06-22
Classification: G01V

Abstract:
1. A method for detecting objects within a monitoring zone of a light grid including a predetermined number of transmitters transmitting light rays, a corresponding number of receivers respectively aligned with the transmitters, each aligned transmitter and receiver forming a beam axis each receiver having a receiver output and producing a received signal at the output, and an evaluation unit for generating an object detection signal in dependence on the received signals, wherein the received signals are coupled to separate, parallel inputs of the evaluation unit, the method comprising: cyclically activating the transmitters, one after another; impressing characterizing codes on the transmitting light rays of the individual transmitters; simultaneously activating the receivers such that only the received signal from the receiver corresponding to the activated transmitter is recorded and stored in the evaluation unit by muting the inputs of the evaluation unit to which the received signals from the remaining receivers are coupled; verifying the correctness of the codes impressed on the transmitting light rays by evaluating the stored received signals in the evaluation unit; and verifying the sequence of received transmitting light rays by evaluating the stored received signals in the evaluation unit.