CONTROL CIRCUIT FOR GRINDING BLADE

摘要

PURPOSE:To detect the length of defective portion of a blade by converting the reflecting light in the light of a projector to electric signal so as to produce status signal and by detecting the width of defective signal in comparison with detecting signal therewith. CONSTITUTION:The reflecting light signal obtained by a light receiving device 5 is divided into two parts passing through a preamplifier 6 and one gets into the first comparator 9 passing through an amplifier 7 and the other gets into the first comparator 9 passing through a low-path filter 8 and then compared and calculated therein. That is, the signal (c) getting out of the low-path filter 8 becomes a reference signal of the first comparator 9 and acts to adjust the output to be zero in comparison with the signal in a regular state of a blade without any defects, thereby removing the influence with respect to direct current fluctuation and a blade breakage detection with high reliability can be performed.