| 摘要 |
PURPOSE:To prevent the occurrence of malfunction due to a mutual interference even if a large number of photoelectric switches are placed in parallel, by a method wherein noise is prevented from exercising the influence by detecting the presence of the noise during a period right before a projecting pulse is generated and by delaying the generation of the projecting pulse. CONSTITUTION:If a photo noise component is produced at a collecting signal i, an output k is produced from an AD circuit 33. The output k is inputted to an OR circuit 42, and thereby an extra pulse other than a Q-output of an FF12 is added to an output l of a circuit 42. As a result, an FF13 is caused to trigger excessively, whereby an output f of an AND gate 32 is immediately brought to LOW, and simultaneously, a timing of a projecting pulse e from an AND circuit 31 delays. Or, if a noise enters right before the projecting pulse e is going to be generated, the projecting pulse e is transmitted in delay by a time for which a photo noise will be lost. This prevents the occurrence of malfunction such as operations to process light, entering from other adjoining photo source switch, as a regular reflection light although the projecting pulse e is transmitted as it is, there is no an object to be detected, and there is also no reflection light. |
