Attached is a sample model built with FlexSim 7.5.4 that demonstrates using fixed-interval trays to move objects around a conveyor system, like a cross-belt sorter.
How it works:
The loop section has a custom Conveyor Type with "Power And Free" checked. It also uses a Motor object to synchronize the dog positions around the full length of the loop.
A Source feeds this conveyor loop with Tray flowitems as the fixed-interval slots where flowitems can enter.
The model uses 3 Photoeye Types.
The first is on each upstream conveyor to stop the item when it blocks the photoeye.
The second is on the sorting conveyor to resume the stopped item.
Then the clear event of the first photoeye moves the item into the tray objects.
The third photoeye type has an itemType label, and it moves the matching flowitems out of the trays into dummy queues that redirect the flowitems to an entry transfer to continue down the appropriate conveyors. In a real model, you should probably hide the shapes of these redirection queues.
The individual photoeyes are assigned these photoeye types and reference other objects using center ports so that you can easily customize entry/exit locations and positioning of these photoeyes.
The transfers from the upstream conveyors to the loop have been purposefully deleted because the clear logic of the photoeyes is explicitly moving the flowitems into the trays.
Conveyor Cross-Belt Sorter