slackjaw
Member
Hi all,
I am hoping some one among you may have thought up a clever solution for this: I am working on a line that uses a photoelectic sensor to detect the presence of tablets. The sensor itself works just fine - when a tablet passes between the emitter and the receiver, the output of the sensor is set (i.e. TRUE of high). Otherwise, when no tablets are present, the output of the sensor is reset (i.e. FALSE or low)
However, the line is periodically dismantled and then reassembled for maintenance activities. Recently, the line was reassembled, but the photoelectric sensor was not plugged in (yes, I am serious).
Because the sensor is only set when it senses a tablet, the automation system cannot tell the difference between:
(1) the sensor is operating normally, but there is no tablet present
(2) the sensor is not powered
Is there some standard way for automation logic to verify the presence of a digital input in this scenario? For instance, if the sensor were normally set, and only reset when a tablet was present, then I could add logic to verify that the sensor was at least present and operating. Sadly, there is no option to change the sensor behavior.
I could source a new sensor to suit my needs, but there would be a tremendous amount of paperwork involved...
I am hoping some one among you may have thought up a clever solution for this: I am working on a line that uses a photoelectic sensor to detect the presence of tablets. The sensor itself works just fine - when a tablet passes between the emitter and the receiver, the output of the sensor is set (i.e. TRUE of high). Otherwise, when no tablets are present, the output of the sensor is reset (i.e. FALSE or low)
However, the line is periodically dismantled and then reassembled for maintenance activities. Recently, the line was reassembled, but the photoelectric sensor was not plugged in (yes, I am serious).
Because the sensor is only set when it senses a tablet, the automation system cannot tell the difference between:
(1) the sensor is operating normally, but there is no tablet present
(2) the sensor is not powered
Is there some standard way for automation logic to verify the presence of a digital input in this scenario? For instance, if the sensor were normally set, and only reset when a tablet was present, then I could add logic to verify that the sensor was at least present and operating. Sadly, there is no option to change the sensor behavior.
I could source a new sensor to suit my needs, but there would be a tremendous amount of paperwork involved...