| 摘要 |
PURPOSE:To prevent the malfunction of a photoelectric switch, by respectively setting first and second stability levels to the high and low level sides of the matter detecting reference level of a photoelectric switch. CONSTITUTION:Pulse beam is emitted from a beam-emitting element from a drive circuit 1 and reflected from matter X to be detected to be received by a beam-receiving element 3 and the received beam is inputted to a signal generation circuit 5 through a amplifying circuit 4. First and second stability signal generation circuits 51, 53 are respectively mounted to the high and low level sides of the reference level of a matter to the high and low level sides of the reference level of a matter detection signal detection circuit 52. When a first stability signal is not generated during the output of a detection signal, a first alarm signal is outputted and, when the detection signal is again outputted when a second stability signal is succeedingly outputted after the output of the detection signal has been stopped, a second alarm signal is outputted. Therefore, when matter detection operation is normally performed but unstable, the malfunction of a photoelectric switch can be prevented. |
