Optoelectronic dimensional control system - uses two pairs of photoreceivers detecting positive and negative tolerance respectively

摘要

The ophelectronic dimensional control system uses live pairs of photoreceivers (2, 22, 23, 24). Each of these pairs is mounted between two electrical supply conductors with an electrode common lothers two receivers. The signal on the common electrode measures the difference in illumination of the two photoreceivers of the pair. This difference signal controls the setting of a two state electronic circuit for this pair of photoreceivers. The light beam is partially marked near to the middle position of the mobile element to be controlled. This middle position corresponds to equal illumination of each pair of photoelectric receivers. The masking is such that the detection of non-equal illumination of a pair of receivers corresponds to positive overshoot of predetermined dimensional tolerance. The detection of inbalance of illumination of the other pair of photoreceivers corresponds to a negative overshoot of tolerance.