Shift Registers 271 (b) Control of a paint sprayer in a booth through which items pass on an overhead conveyor so that the paint is switched on when a part is in front of the paint gun and off when there is no part. The items are suspended from the overhead conveyor by hooks; not every hook has an item suspended from it. Lookup Tasks 11. Find out the details of shift registers available with PLCs from a particular range from a specific manufacturer.