PURPOSE: To prevent the pulse modulation type photoelectric switch from malfunctioning owing to pulse light such as projection pulse light from, for example, another photoelectric switch which is arranged nearby.
CONSTITUTION: This photoelectric switch is provided with an oscillation period control circuit 9 which inputs both the inverted signal (g) of the photodetection pulse signal (2nd photodetection pulse signal) from a flip-flop 7 and the projection pulse signal (a) from a pulse oscillation circuit 1, detects the photodetection phase of the photodetection pulse light for the projection pulse signal from the signals, and outputs a control signal (h) for varying the pulse period of the projection pulse signal (a) for the pulse oscillation circuit 1 according to the photodetection phase.
MAKINO SETSUO
SHIMAJI NAOHIRO
TANIGAWA KIYOSHI
FUJI ELECTRIC CO LTD