conveyor in manual mode disturbed Vision

As the headline reads. I try to make sure that we can run the conveyor belt manually with a switch "manual / automatic" and then a twisted back / forward. The signals work as they should, but as soon as I try to get it in some way, it disrupts the vision system. Either the conveyor belt does not work or the vision system does not work or none of it .. Someone who can help me look at it?