Light barrier operating method has new switch threshold value obtained from measured maximum and minimum light intensities each time light stop is moved

摘要

The light barrier operating method determines the maximum light intensity of the light source (3) used for illuminating a photosensitive element (4) in the open position of a light stop and the minimum light intensity in the closed position of the light stop, for defining an intermediate switch threshold value. When the latter is exceeded by movement of the light stop, the maximum and minimum light intensities are re-measured and a new switch threshold value is provided.