How to make a queue pull multiple items from many ports?

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Aditya Kamath asked Oct 5, '16 Aditya Kamath commented Oct 6, '16

How to make a queue pull multiple items from many ports?

I have three queues feeding into one larger queue(this could also be any other process). How can I specify the pull strategy such that a downstream process or a queue will be able to pull 'x' number of parts from Queue 1, 'y' number of parts from Queue 2 and 'z' number of parts from Queue 3? I tried using the ItemType by port option in the pull strategy but that doesn't let me specify the number of each ItemType to pull.

pull-specific-number-of-parts.fsm

Software Version:

FlexSim 16.2.0

pull strategy queue content

pull-specific-number-of-parts.fsm (17.5 KiB)

Answer 1 · 2016-10-05T22:08:05Z

Regan Blackett answered Oct 5, '16 Aditya Kamath commented Oct 6, '16

I would approach this using a combination of 3D elements and process flow for control, in conjunction with a a Global Item List

I have three Queues which during send to Port, 'Push' their flowitems onto a partitioned Item List, where each Queue has it's own partition. Int he Process Flow I create a token that represents the downstream Queue's ability to pull flowitems. The token executes 3 Pull from List activities each that pull an amount from each of the upstream Queue's partitions in sequence (this could be modified to all them to be pulled in any order too, but from simplicity it goes through each in sequence). Once the desired items have been Pulled from the List, the 'Move Object' activity puts them in the Downstream Queue.

See the Attached model and let me know if this helps.

queue-pull-logic.png (204.2 KiB)

queue-list-pull.fsm (23.0 KiB)

· 1

Aditya Kamath commented · Oct 06, 2016 at 03:47 PM

@regan.blackett Thanks! I tried it out for my model and it works beautifully. I'm really beginning to like the process flow approach.

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Answer 2 · 2016-10-06T13:15:35Z

Ralf Gruber answered Oct 6, '16 Aditya Kamath commented Oct 6, '16

Is there a reason, why you don't try with a combiner instead of your larger queue? That object is specifically designed to do, what you are asking for. Use it in batch mode to keep the single FlowItems you collect from the input queues.

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Aditya Kamath commented · Oct 06, 2016 at 04:16 PM

@Ralf Gruber

Thank you Ralph. I had assumed that you always need a pallet to group items in a combiner. I did a little more research after you mentioned this and I think I can do it without a pallet as well.

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Answer 3 · 2016-10-06T06:00:53Z

Joerg Vogel answered Oct 6, '16

Pulling a defined number of items has nothing to do with any Pull Requirement or Pull From function. It is a general flow control that you need here. You do this by closing or opening the input or output of the objects in your material flow. In an Object that has to pass a destinct number of items you count those send items and then close the output. If you need more items you reset the label and count again.

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