Abstract: Detection of interfering light is performed based on an interfering light detection timing signal Si set immediately before a blockage detection timing signal Sr. If interfering light is detected consecutively with respect to the same optical axis according to interfering light detection timing, the length of blank period tb is reduced to shift the positions of pulses of the blockage detection timing signal, thereby avoiding overlap between these pulses and pulses of interfering light on the time axis. In this manner, mutual interference between multiple-axis photoelectric sensors can be prevented without providing sync line wiring between the photoelectric sensors.

Abstract: Detection of interfering light is performed based on an interfering light detection timing signal Si set immediately before a blockage detection timing signal Sr. If interfering light is detected consecutively with respect to the same optical axis according to interfering light detection timing, the length of blank period tb is reduced to shift the positions of pulses of the blockage detection timing signal, thereby avoiding overlap between these pulses and pulses of interfering light on the time axis. In this manner, mutual interference between multiple-axis photoelectric sensors can be prevented without providing sync line wiring between the photoelectric sensors.