question

@Thao B

The problem you were encountering was due to the timing of the execution of some of your custom code:

if (current.Qty == 0) {
	current.rowno = current.rowno + 1;
    int rowno = current.rowno;
    
	if (rowno <= Table("Batch").numRows) {
         int qty = Table("Batch")[rowno][1];
         model().find("Queue3>variables/maxcontent").value = qty;
         model().find("Queue3>variables/batchsize").value = qty;
         current.Grade =  Table("Batch")[rowno][3];
         current.Type =  Table("Batch")[rowno]["Type"];
         current.Qty =  Table("Batch")[rowno][1];
   }
}

You had this code within the OnEntry trigger of Queue3. What would happen is after the last item of Batch 3 entered, the queue max size and batch size would update to 5 (based on Batch 4). This would cause an extra item to be able to enter before Batch 3 left, leading Queue3 to send out 5 items instead of 4. Since Queue4 was expecting only 4 items (its batch size set to 4 from the item.batch label), this caused a series of problems that led to the lane jamming up.

One solution is to move this code to an "On Exit" trigger in Queue3, so that the change in labels doesn't affect the items currently in the queue. I did this in this updated model and it works fine: panellineanswer.fsm