Patent ID: 9128201
Filing Date: 2015-09-08
Classification: G01V

Abstract:
1. A light grid with a transmission unit comprising a plurality of individual light transmitters and a transmitter control for activating the individual light transmitters, and with a reception unit comprising a plurality of individual light receivers corresponding to the individual light transmitters and comprising an evaluation unit connected to the individual light receivers, the evaluation unit configured to detect an interruption of a light beam from an individual light transmitter to a corresponding individual light receiver and optically synchronized with the transmitter control, wherein, the transmitter control transmits a synchronization signal to the individual light transmitters simultaneously and in parallel, and each of the transmitters responds to the synchronization signal by transmitting an object detection signal with a time offset unique to that transmitter, and each of the receivers responds to the synchronization with a time offset unique to that receiver, wherein the time offsets of the transmitters and of the receivers correspond to predetermined ones of the light paths; the reception unit transmits a synchronization signal corresponding to the synchronization signal transmitted by the transmitter control, to the individual light receivers; the evaluation unit simultaneously receives signals from the receivers corresponding to reception of light beams via multiple individual light receivers and to determines a time offset value of signals from the receivers to determine a point in time of reception of the signals with respect to the synchronization signal, the point of time corresponding to the predetermined ones of the light paths.