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Afthab L avatar image
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Afthab L asked Afthab L commented

How to set acquiring priority from two conveyors?

Hi,

I was wondering how I go about setting the acquire priority for two conveyors. The priority for acquiring the items should always be for the main conveyor as opposed to the side transfer conveyors. I'm basically trying to set a distance such that the items from the side transferred conveyors do not bump into the items from the main conveyor during the side transfer and there is always a distance maintained.1625807781591.png


Any help or suggestion would be appreciated.

Acquire Priority.fsm


FlexSim 21.1.4
conveyoracquire resourceprioirty
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Eric M avatar image
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Eric M answered Afthab L commented

Hi @Afthab L, in addition to the answer to your other question here (link), I think I've found another solution. The reason the priority isn't happening like you expect is because the priority only comes into play when there are 2 items both waiting to enter the restricted area at the same time. When there's only 1 item waiting, it will always be the next item to enter.

The solution I came up with uses a combination of triggers on the control points and process flow. The triggers use the Enter Restricted area activity to keep track of how many items are currently in the area which is stored on a label on DP1 called dp_RestrictedContentArea. Because we never want the main conveyor items to stop, I set the max content of the area to 100. The DP on the entering conveyor is used to create a token in process flow when an item arrives. This item is immediately stopped and then enters a Decide activity. Here's where the token checks if the Label on DP1 is 0 or not. If it's 0, the item will continue. If it's not zero, meaning there are items in the area still, it will be sent to a "wait for event" activity that waits for an item to cross DP1 at which point it will check the area content again. The last thing to do is make sure the area is big enough that the entering item will never block the main conveyor items. Let me know if you have any questions!

acquire-priority-em.fsm


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Afthab L avatar image Afthab L commented ·

Hi again Eric! Thank you very much for the reply. Once again, the ran into the same issue where even when an item is still within that zone the side transfer decides to still enter. Is this perhaps a problem on my end? Time Stamp at 28-30s.The logic that you have stated is exactly what I want but for some reason, the model doesn't seem to run that way. Thank you also for explaining why the priority option wasn't working as I imagined.


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Sorry for the trouble and I appreciate your help! Thank you!

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Eric M avatar image Eric M Afthab L commented ·

This is also a timing issue where 2 items are entering and exiting right around the same time. You can see at 28.97s that one item leaves the area right before the next item enters:

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This then resumes the item on the side transfer even though another item is just about to enter. Again, adjusting the position of the decision points could help get the gap to where you want it to be. Let me know if this is something that will work for you or if you have something else in mind.

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Afthab L avatar image Afthab L Eric M commented ·

This works for me perfectly! Thanks a lot Eric! Really appreciate the work you are doing!

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Roi Sánchez avatar image
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Roi Sánchez answered Afthab L commented

You are already prioritizing the items on the main conveyor. If you take a look at the Decision Point where the Release Area is carried out you can see the Priority criteria:

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Afthab L avatar image Afthab L commented ·

But at 25.81 seconds it stops the main conveyor in order to acquire the side conveyors item, this causes the items in the main conveyor to stick together. How would I prevent this from happening? If anytime there's an item near that decision point, the side conveyor should hold it's transfer. Thank you for taking a look and I appreciate the help! Honestly.1625815514669.png

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