How to release and/retain flowitems based on a schedule?

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Ruben Mariduena asked Nov 6, '16 Sam Stubbs commented Nov 7, '16

How to release and/retain flowitems based on a schedule?

Please see sample model attached. This is a shipping scenario where we are shipping a number of items per voyage. The global table "MArrivalTable" shows a sample schedule of items we need to ship and all items have to be retained/released at the "MF Site" queue. Our model needs to be able to look at the schedule and only release items from the queue (on their ready dates) when the items in the voyage are in succession. If there's an item from another voyage in between, all of the items from the original voyage now have to wait until the last item in that voyage to be ready for them to be released one by one. The illustration I have provided shows when every item in the sample model should be released. Items in green mean that they leave as soon as they are created, items in red mean that they wait until the last module on that voyage for all of them to be released. Our input schedules are going to be made out of hundreds of items and voyages so we need to somehow make the model be able to determine this by itself. Is there any way to achieve this in the queue or any other place in the model?

modelsample411.fsm

voyage-schedule-sample.png

Software Version:

FlexSim 16.2.1

flowitems schedule release

voyage-schedule-sample.png (91.3 KiB)

modelsample411.fsm (275.4 KiB)

Answer 1 · 2016-11-07T14:44:55Z

Sam Stubbs answered Nov 7, '16 Sam Stubbs commented Nov 7, '16

What I would probably do, is use a list in conjunction with a Scheduled Source Process Flow logic. Have the shipments that are waiting at your "MF Site", be pushed onto a list once they arrive. Then set up a Scheduled Source in a Process Flow, that at the required time interval or schedule, pulls the item(s) from that list and moves them as needed in your model.

I've created a small example of how you could set this up.

scheduledpull.fsm

scheduledpull.fsm (20.2 KiB)

· 2

Ruben Mariduena commented · Nov 07, 2016 at 08:51 PM

@Sam Stubbs

Thank you for the input, I think this is the direction we need to go to create this logic. But how can I make the model identify which are the shipments that have to wait and which ones are the ones that can be transported as soon as they are created? If you look at the schedule.png some shipments don't have to wait at the MF Site. Our schedules will have 300+ shipment numbers so we can't manually determine which shipments will wait.

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Sam Stubbs ♦ Ruben Mariduena commented · Nov 07, 2016 at 09:47 PM

I would include that information as a label on the item. Then write logic accordingly. If label tells it to wait, then it's pushed to the list, if the label marks that it doesn't need to wait, then it can ship right away, or it's put onto the front of the list etc. You can use labels to control this. You can even have a field added to the List's properties that corresponds with the label on the item so that you could query the list for specific items too.

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