question

Yifei Wang avatar image
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Yifei Wang asked Sam Stubbs commented

How to let the transporter identify the shortest queues and get the items needed from that queue?

Hi FlexSim staff,

I am having some troubles with telling the transporter to identify the shortest queue among the ones that transporter is in charge of. Then, get the items needed for the shortest queue from any rack which contains certain itemtype. Please look at the attached model that one of FlexSim technicians built. Transporter 1 is in charge of Queue 1, 2 and 3. Each time Transporter1 finish unloading items on any Queue, he should identify which Queue among Queue 1, 2 and 3 has the least items. Let's say Queue 2 has the shortest line this time. Since Queue 2 needs itemtype1, Transporter should go to any rack to get itemtype1. Can someone made some adjustment on this model? Thank you!

simplesortingmodel-autosave.fsm

FlexSim 16.1.0
forklift
simplesortingmodel-autosave.fsm (23.6 KiB)
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Sam Stubbs avatar image Sam Stubbs ♦ commented ·

So the problem is that it IS going to the shortest cue, but the Send To Port function is being called from when the item gets into the rack, not when the Transporter picks up the item. So when the item first gets into the rack it looks for the shortest cue, not taking into account any items currently being carried there. (So if 5 items all arrive in the racks in a short amount of time, they may all see that Queue1 is the shortest, so they all call their function to go to Queue1... so it looks like Queue1 is getting too many items before the others get their share too.)

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Yifei Wang avatar image Yifei Wang Sam Stubbs ♦ commented ·

How can i change that to make sure the transporter meets my need?

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Sam Stubbs avatar image Sam Stubbs ♦ Yifei Wang commented ·

Brandon's answer is a good way to go. That way the destination is handled when the operator loads the item rather than when the racks "push" the item onto the list.

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1 Answer

Brandon Peterson avatar image
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Brandon Peterson answered

Yifei,

To get your model to do what you wanted I did the following:

  1. I added a dynamic Expression Field to the List "TSList" in your model called "QContent" that is the content of the destination queue. The content is recalculated each time the Lists is pulled from.
  2. I modified the OnResourceAvailable trigger so that it would order the task sequences in the list based on the "QContent" dynamic field. I simply added "ORDER BY QContent ASC" at the end of the Query field.

I have attached the model that I tested the changes in.

Good Luck,

Brandon


simple-sorting-model-v2016-1-01.fsm (25.3 KiB)
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