Problem with preemptions

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Oscar C13 asked Jun 9, '22 Jason Lightfoot edited Jun 10, '22

Problem with preemptions

Hello everybody,
I have a problem with mi moden and I tried to replicate it with this example.

While an activity that lasts 60 seconds is being executed (being in fr1), every 40 seconds the operators must go to FR2 and stay 5 seconds. When the operator finis the activity that he is doing in fr1 he has to go to fr3 but he have to keep in mind that every 40 secons he still has to go to fr2. fr2 has to go a totl of 2 times. I made a tracked variable so that it looks at the times it has already fone fr2 and make the save context with differente values. It gives me an error and it doesn´t work either.
Any ideas?

preempt.fsm

Software Version:

FlexSim 22.1.2

preemption dispatch activity milestone tasks

preempt.fsm (40.9 KiB)

Answer 1 · 2022-06-09T18:02:55Z

Jason Lightfoot answered Jun 9, '22 Jason Lightfoot edited Jun 10, '22

Please take a look at this post where the use of task sequences and milestone is outlined. This is a better way to preempt that the token context saving method you have tried.

This is the example model:

interruptionv2-jl3.fsm

interruptionv2-jl3.fsm (51.5 KiB)

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Oscar C13 commented · Jun 09, 2022 at 06:47 PM

Thanks for your answer

The problem with the attached model in your answer is that it is not doing exactly what is requested. The 10 seconds are counted all the time, and not from the moment the operator arrives at queue2. Another problem is that it is an infinite loop, it does not stop when the operator has been in queue2 for 40 seconds.

On the other hand, I didn´t understand the use of milestones and how they can help.

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Jason Lightfoot ♦ Oscar C13 commented · Jun 09, 2022 at 07:52 PM

It was from another question (linked) so I didn't expect it to have the same parameters as yours.

It isn't in an infinite loop - the 'core system' task completes at 479 seconds, having been preempted away for the other 439 seconds.

It's an example of how to preempt a task executer using the best method. If you had any number of core tasks at different locations , the use of the milestone allows you to preempt to a different location and not worry about knowing where the operator needs to return to complete a task - the milestone does it for you. Change the timing and see how it works.

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Oscar C13 Jason Lightfoot ♦ commented · Jun 10, 2022 at 07:00 AM

Sorry really, but I don´t understand how your model works. What makes it stop at that time?

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