Racking: First available?

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Adarsh Jeyes asked Aug 03 2016 at 1:59 PM Phil BoBo commented Aug 12 2016 at 7:08 PM

Racking: First available?

Find attached model (made in FlexSim 7.7.2).

I'm trying to send all the items from the various queues to the first rack (ground storage), then the second, and so on. The first available option doesn't seem to work. Any help would appreciated. 03-08-16-rack-first-available.fsm

Software Version:

FlexSim 7.7.2

rack racks first available floor racks flexsim 7.7.2

03-08-16-rack-first-available.fsm (21.2 KiB)

Answer 1 · 2016-08-03T15:09:22Z

Joerg Vogel answered Aug 03 2016 at 3:09 PM Phil BoBo commented Aug 12 2016 at 7:08 PM

The Fixed Object queue checks the current content of the first available Rack and the variable nroftransportsin of this rack to decide if there is enough capacitiy left to create the tasksequence for the transport. If there isn't any capacity (stored item + item in transit) left the queue creates the transport tasksequence for the next available rack. That the transporter works on a tasksequence for the second rack has something to do with the ability how many item's a rack can receive. If a rack is blocked by another transporter the dispatcher moves the next available tasksequence to the transporter. All this is documented in the manual for the fixed resource object.

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Adarsh Jeyes commented · Aug 04 2016 at 10:42 AM

Hi Jörg Vogel

Firstly, thanks for your response!

I read through the manual and understood how the nroftransportsin gets updated as soon as a flowitem enters the queue. With each flowitem entering the rack, the nroftransportsin and nroftransportsout get updated, and the task sequences are created.

However, I have ensured that the Flow in each queue is set as 'First Available', which should make sure that the first 10 items (max content of the rack) received at ANY of the queues should be assigned to the first rack (variable nroftransportsin = 10, nroftransportsout = 0). With each item entering the rack, the nroftransportsin should decrease by 1, and the nroftransportsout should increase by 1.

But that is not how FlexSim is assigning the flowitems to the rack. Take a look at this model:

03-08-16-rack-first-available-ver-2.fsm

Can you show me how to get the first 10 items received at any of the queues to be assigned to the first rack?

0 ·

03-08-16-rack-first-available-ver-2.fsm (22.8 KiB)

Phil BoBo ♦♦ Adarsh Jeyes commented · Aug 12 2016 at 7:08 PM

Update to FlexSim 2016 Update 1.

From the release notes:

"Changed the way that fixed resources (except the Combiner) receive items when they are being transported in. Previously, when they were notified that an item was being transported in, they would close their inputs and create an event to receive the next item. This would cause problems if the upstream objects had multiple items to send because their routing strategy would work differently when transporting vs not transporting. We have fixed this so that routing strategies will work the same when transporting as when not transporting. This may change the way that old models work because it changes the events that are created, and, obviously, it fixes routing strategy logic."

If you open this model in version 16.1.2, it behaves the way you want it to.

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