Multiple optical axis photoelectric sensor

A method for determining a light state of a detection area of a multiple optical axis photoelectric sensor, said detection area comprising a plurality of optical axes between a projector and an optical receiver of the photoelectric sensor, comprising the steps of:

• validating sequentially the optical axes,
• conducting a scan processing of the optical axes,
• detecting an existence or non-existence of light entrance of the validated optical axes,
• determining a light state of the detection area formed by the optical axes based on a result of the optical axis scan processing,
• measuring a number of times from the optical axis scan processing in which a result is obtained that the detection area is in a light entrance state, and a number of times from the optical axis scan processing in which a result is obtained that the detection area is in a light obstruction state,
• switching an output to an on-state or an off-state according to the result of the measuring step,
• determining if a light state is caused by a malfunction by updating a first variable and a second variable according to every determination result of the optical axis scan processing, and
• notifying a user when the light state is due to the malfunction,
• 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.

A method for determining a light state of a detection area of a multiple optical axis photoelectric sensor, said detection area comprising a plurality of optical axes between a projector and an optical receiver of the photoelectric sensor, comprising the steps of:

• validating sequentially the optical axes,
• conducting a scan processing of the optical axes,
• detecting an existence or non-existence of light entrance of the validated optical axes,
• determining a light state of the detection area formed by the optical axes based on a result of the optical axis scan processing,
• measuring a number of times from the optical axis scan processing in which a result is obtained that the detection area is in a light entrance state, and a number of times from the optical axis scan processing in which a result is obtained that the detection area is in a light obstruction state,
• switching an output to an on-state or an off-state according to the result of the measuring step,
• determining if a light state is caused by a malfunction by updating a first variable and a second variable according to every determination result of the optical axis scan processing, and
• notifying a user when the light state is due to the malfunction,
• wherein the first variable is updated while the determination result that the detection area is in the light obstruction state is continuously made, and the second variable is updated according to the determination result that the detection area is in the light entrance state.

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 a 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 obstruction state is continuously made, and the second variable is updated according to the determination result that the detection area is in the light entrance state.