Light barrier and method for pulsed operation in which the incidence of extraneous light on the detector can be detected and compensated for

摘要

Pulsed operation of a light barrier that can be operated in a normal mode and in a compensation mode includes repeating a cycle of transmitting electromagnetic radiation over a transmission period recording measured radiation values at various measurement times and establishing whether extraneous light is incident on the detector by examining a measured value curve of the recorded measured radiation values. The respectively next cycle in the normal mode being run through when no extraneous light is incident, and in the compensation mode when extraneous light is incident, at least one compensation measure being carried out in the compensation mode in order to compensate the influence of extraneous light.

主权项

1. A method for the pulsed operation of a light barrier that can be operated in a normal mode and in a compensation mode, there being run through repeatedly a cycle that comprises the following steps:
a) transmitting electromagnetic radiation over a transmission period Δttransmit by means of a transmission device, b) recording measured radiation values Ii of the electromagnetic radiation at various measurement times tmeas within the transmission period Δttransmit by means of a detector, and c) establishing whether extraneous light is incident on the detector by examining a measured value curve of the recorded measured radiation values Ii, the respectively next cycle in the normal mode being run through when no extraneous light is incident, and in the compensation mode when extraneous light is incident, at least one compensation measure being carried out in the compensation mode in order to compensate the influence of extraneous light, wherein the measured value curve is examined for a positive curvature.