question

When you pull from the list it evaluates a query against all the entries on the list. So in your model if there’s an item that’s been in the queue longer than 10 time units it will pull that item. However, if none of the items meet the requirements of the query it creates a backorder. By default back orders on a list are only re-evaluated when a new entry is pushed to the list and it’s only re-evaluated for that single new entry.

So in your model the processor pulls at the start of the run, gets nothing and so creates a backorder. From then on the query is only evaluated against the new items entering the queue, all of which are age 0 - thus it never pulls anything.0

What you need to do is make the list reevaluate backorders at more appropriate times. You can set up back order re-evaluation events on the Back Orders tan of the list. You can also use the List’s reevaluateBackOrders() method to force the list to re-evaluate backorders whenever you want. There’s also a checkbox on the list that tells the list to re-evaluate backorders for all entries whenever a new item is pushed on the list.

See this previous question for more information: https://answers.flexsim.com/answers/24468/view.html