Light grid

A light grid for detecting objects within a monitored zone, comprising:

• a predetermined number of transmitters to emit light rays, the transmitted light rays of the individual transmitters being imprinted with a code that characterizes the light rays emitted by the respective transmitters, the transmitters being activated cyclically and successively;
• corresponding receivers respectively aligned with the transmitters to form transmitter/receiver pairs, each pair defining a beam axis, the receivers being activated continuously for reception of the transmitted light rays, each receiver having a receiver output and producing a received signal at the output;
• an evaluation unit coupled to the receiver outputs, the evaluation unit generating an object detection signal in dependence on the signals received and present at the receiver outputs, the received signals being conducted in parallel to separate inputs of the evaluation unit, wherein respectively only the signals received at the receiver associated with the active transmitter are recorded and stored in the evaluation unit by muting the inputs onto which the signals received by the remaining receivers are conducted, and wherein the correctness of the codes transmitted by the transmitters and their sequence are checked in the evaluation unit by evaluating the stored received signals.