In a warehouse or distribution center, many times we come across a situation where conveyor bed stops due to a blocked photo eye. However, physically there is no jam situation. This happens because of a misalignment of photo eye or the photo eye itself is bad.

If site do not have a spare photo eye to replace or production cannot be stopped because of peak hours, in such situations, it is required to bypass that specific photo eye. In technical words it is required to force ON the photo eye if it is configured as normally closed. Or it is required to force OFF if it is configured as normally open. This action will remove false jam condition and conveyor will start running.

Please note that this is a temporary workaround so that production continues. Permanent solution is to fix misalignment or replace faulty photo eye during a downtime window. We should not keep any digital or analog input or output in a forced condition continuously.

Now let’s see how we can force ON a photo eye digital input which is configured as normally closed. 

In the view center we have identified a tote routing merge lane #31280 dash IQZF.

And a photo eye to detect jam condition on this conveyor bed.

Photoeye number is EE31280 dash one.