question

joey avatar image
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joey asked Braydn T commented

How do I set up item retrieval?

HI, How do I pull an item out of all 4 queues?

I want to pull the list from the queue 1,2,3,4 to QueueOut.

Pulling conditions.

-Frequency of pulling items from all 4 queues.

Item 1 is an exponential statistical distribution and Item 2 is a bernoulli statistical distribution.

-Volume of pulling items from all 4 queues of 2 items

Is it possible for me to determine the amount of pulling each time in a statistical distribution format? If possible, I want both items to be exponential statistical distributions. But if it is impossible, I want to determine the amount of pulling each time, ie item 1, pulling 10 times and item 2, pulling 5 times.

all-transporter.fsm

Thanks.

FlexSim 19.0.2
queuepullstatistical distribution
all-transporter.fsm (55.1 KiB)
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1 Answer

Braydn T avatar image
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Braydn T answered Braydn T commented

One of your issues is your tokens in your filling subflows never reach "Push to List" so there is nothing to pull from when they go to pull from the list. Look at your Transporter In subflows and double check that the tokens are reaching the "Finish" so that the tokens can be pushed to a List. However, that isn't causing the exception. When there is an exception in process flow it tells you what the task type was. In your case it is the Travel task on the Transporter out. You are telling it to go to "token.Q1" or "token.Q2" which is a label you have never assigned to a token. You need to make the destination the location of the item you pulled from the list. You can add ".up" to the end of a token and it will choose the current location of that token.

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Braydn T avatar image Braydn T commented ·

Hey @joey

We weren't exactly sure with what you mean by "Item 1 is an exponential statistical distribution and Item 2 is a bernoulli statistical distribution."

We assume you meant a statistical distribution in the amount of time it takes to load. We created a simplified process flow that moves the items from Queue In, to the their respective Queues, and then another Process Flow that picks them up in groups of two (which is what we assumed you meant by "Volume of pulling items from all 4 queues of 2 items") and drops them off at Queue Out.

Please let us know if this isn't what you actually meant, and if it isn't please provide us with the end goal of your model so we can help you with it.

Attached is the updated model. all-transporter-edit.fsm

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joey avatar image joey Braydn T commented ·

Hi @Braydn T Thank you for your help.

But the model you attached is not the logic that I want.

I want to pull the list from all 4 queues to the QueueOut.

There are 2 logic that I want.

1)Frequency of pulling items from all 4 queues.(Similar to inter arrivaltime).

I mean when the transporter receives the item from the queue 1,2,3,4 Of 2 items in the form of statistical distribution.

2)The amount of items that will be drawn from each 4 queues

Is it possible for me to determine the amount of items to pull? Each time has a statistical distribution(Item of Type 1 pull 10 items, pull 1 item per count, 10 rounds)

Do you understand the logic that I ask?

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Braydn T avatar image Braydn T Braydn T commented ·

Hey @joey

So to clarify, you want the transporters to be dispatched to go pick up items from queues 1-4 on a statistical distribution, not the amount of time they take to be in a statistical distribution.

And you want the number of items to be picked per transporter trip to be a statistical distribution.

If you want them to be dispatched to pick on a statistical distribution, I would make your Transporter Out subflows into their own separate subflows like this:

On your Pull from List, edit your OnWaitTimerFired so that it releases the token down Port 2 (to the sink) so that it doesn't sit at Pull from List forever if there are no items in the List.

and have your queue filling subflows push the items onto the list like this:

That way you can set the Inter-arrival source to whatever statistical distribution you like, and it will create a token telling that transporter to go pick up a box on that statistical distribution.

To make the number of items picked per Transporter trip, you should change the Request Number field on your Pull from List to your desired statistical distribution.

Make sure you have your Release Token set in the OnWaitTimerFired field like we mentioned before, in case there are no items in the List when you Pull.

Let us know if that works for you.

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subflow.png (15.8 KiB)
subflow3.png (17.5 KiB)
pull-list.png (20.0 KiB)
subflow2.png (12.7 KiB)
joey avatar image joey Braydn T commented ·

Hi @Braydn T

I have a question about your description. I do not know where this guide will be.

Can you explain more?

Thank you for your help in advance.

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Braydn T avatar image Braydn T Braydn T commented ·

Hey @joey

Its under the properties for Pull From List. Make sure you have the Use Max Wait Timer box checked, and then edit the field there.

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joey avatar image joey Braydn T commented ·

HI @Braydn T

I followed your advice. But it looks like my model has a problem. I don't know what the problem is. I want you to see my model.new-model.fsm

And I have another question(I have to create a list Added more, right? And if creating more, do I have to create Global Lists as well? And then in Global Lists, what values do I have to choose?

)

Thanks.

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new-model.fsm (56.4 KiB)
11.png (38.5 KiB)