Unloading from crane to a processor in its downtime

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felicity asked Jan 8, '24 felicity commented Jan 28, '24

Unloading from crane to a processor in its downtime

Hi!

I have a question regarding task preemption and timetables. Now I know how to make the operators and other resources such as cranes finish the task at hand before going on downtime. What I don't know is how to let my empty processor receive items (but not start processing) from the crane and then start downtime.

This causes the crane to stay in a "blocked" state not able to unload item to the processor until the end of downtime which causes problems in the overall production cycle time.

I will attach a simpler version of my model here and at the end of day 1 you can see this happening.

I appreciate your help in advance

test- preemption.fsm

Software Version:

FlexSim 22.2.0

crane timetables preemption down behavior

stop-object.png (67.9 KiB)

test-preemption.fsm (51.9 KiB)

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5 |100000

Attachments: Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

Jason Lightfoot ♦♦ commented · Jan 12 at 02:50 PM

Hi @felicity, was Felix Möhlmann's answer helpful? If so, please click the "Accept" button at the bottom of their answer. Or if you still have questions, add a comment and we'll continue the conversation.

If we haven't heard back from you within 3 business days we'll auto-accept an answer, but you can always comment back to reopen your question.

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Answer 1 · 2024-01-08T07:47:18Z

Felix Möhlmann answered Jan 8, '24 felicity commented Jan 28, '24

You can use the await statement to delay the stopping of the processor until an item has entered it, if the processor is empty when the down function fires and the crane is currently moving an item.

You could build the same logic in a Process Flow and trigger it by creating a token in the down function (Token.create()) to start it.

test-preemption-fm.fsm

1704699935347.png (20.3 KiB)

test-preemption-fm.fsm (130.9 KiB)

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5 |100000

Attachments: Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

felicity commented · Jan 09 at 06:33 AM

@Felix Möhlmann Thank you!

This code was very helpful. I have one question though. As in my main model a group of cranes may unload to a number of processors, what can I use instead of:

Model.find("Crane1").subnodes.length > 0

to insure the same logic for all of them?

(Also, the model works perfectly without the "Create TS" and "Finish TS" activities.

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Felix Möhlmann felicity commented · Jan 09 at 07:17 AM

I'd use a label on the processor to keep track of incoming items and use that in the down function to wait for the arrival.

test-preemption-fm(1).fsm

And yes, the Create TS and Finish TS are not needed. I somehow throught the travel activity was also a task for the crane.

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test-preemption-fm1.fsm (52.9 KiB)

felicity Felix Möhlmann commented · Jan 28 at 11:53 AM

Late reply, but I wanted to thank you for your answer @Felix Möhlmann this works very well.

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