+ Rubber knobs are mounted to the pallet in order to prevent the keg from sliding off. Presence of the anti-sliding rubber knobs is verified by the sytem.
+ Missing or cut centering knobs can not hold the keg safely on the pallet, thus their presence and goog state needs to be controlled.
+ Efficient detection of external elements that might disturb the automatic precessing of the pallets, like shrink foil or similar