Multiple optical axis photoelectric sensor

摘要

A multiple optical axis photoelectric sensor is provided that stops a control output according to light being obstructed in a detection area. First and second variable signals indicate the duration of an optical axis scan processing for which light entrance detection and light obstruction detection are obtained, respectively. The first and second variable signals are updated according to results of each scan in the optical axis scan processing. When the value of the first variable reaches a predetermined first reference value, and when a final value of the second variable is equal to or lower than a predetermined second reference value, a notification is made that the light obstruction is detected due to a malfunction. As a result of this notification, whether output signal of the sensor is erroneously switched due to a cause other than an object of a detection target can correctly be made.

主权项

1. A multiple optical axis photoelectric sensor comprising:
a projector, an optical receiver, a plurality of optical axes between the projector and the optical receiver, at least one selecting circuit configured to sequentially validate the optical axes, a processor coupled to the at least one selecting circuit for conducting optical axis scan processing of the optical axes, an output for outputting a light state of the photoelectric sensor, and a variable update unit configured to update a first variable and a second variable according to every determination result of the optical axis scan processing, wherein the light state comprises a light entrance state and a light obstruction state, wherein the light state comprises the determination result of a detection area being in the light entrance state or the light obstruction state based on a result of the optical axis scan processing, wherein the first variable is updated while the determination result that the detection area is in the light entrance state is continuously made, and the second variable is updated according to the determination result that the detection area is in the light obstruction state.