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Wait for Event and Synchronize activity

@matt.long

In this post, I implemented the logic in a separate model, where the pallet and support board travel on the same conveyor as opposed to tow separate conveyors.

I am trying to wrap my head around the wait for event activity on the board side. The pallet arrives at the station, gets lifted and waits for the board. The wait for event activity then listens to OnArrival trigger on the decision point and should match the label on the incoming item, "Board".

The token gets stuck at this activity and the second Synchronize activity then waits for this token to get released.

I understand that in your model, the wait for event activity listens to the decision point which is on a separate conveyor than the station. Am I referring to the correct token the enters the wait for event activity on the board side?

PSBv4.fsm

Regards,

Amit

FlexSim 20.1.3
flexsim 20.1.3wait for eventsynchronize
psbv4.fsm (58.6 KiB)
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Amit Kulkarni avatar image Amit Kulkarni commented ·

@matt.long, @brandon.peterson

Did you had any chance to look at this issue?

Many thanks!

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1 Answer

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Brandon Peterson answered Amit Kulkarni commented

@amit.k2,

The reason that the token get stuck in the Wait for Event activity is because the activity is waiting for the pallet to arrive at decision point D2. However, the pallet has already arrived and therefore cannot arrive a second time to trigger the event. I would suggest changing the sequencing of your process flow to ensure that the token arrives at the activity before the pallet arrives at the decision point. Another option would be to insert a decide activity before the Wait for Event to check and see if the pallet has already arrived at the DP. If it has then you could skip the Wait for Event activity.

I hope this helps,

Brandon

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Amit Kulkarni avatar image Amit Kulkarni commented ·

@brandon.peterson

I do not understand when you said the activity is waiting for the pallet to arrive at decision point DP2. The wait for event activity at DP2 is waiting for the Board which is created as a request from the Pallet that has gone through a profile check and is waiting at PSBInsertion station. If I understand synchronize activity correctly, the token for Pallet has already arrived at the second synchronize activity and is waiting for the Board token which is stuck at the above mentioned wait for event activity.

Did you mean the event triggered source that creates the board in the first place after listening to the Pallet's arrival at PSBInsertion station on the conveyor is causing the token to get stuck at the wait for event at decision point DP2?

I also tried using lists instead of synchronize activity, but end up getting same result. How should I correctly listen to board's arrival at decision point DP2?

PSBInsertion_Lists.fsm

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psbinsertion-lists.fsm (57.3 KiB)
Brandon Peterson avatar image Brandon Peterson ♦ Amit Kulkarni commented ·

@amit.k2

In your latest model the pallet with the blue box arrives at "PBInsertion" where it is stopped on the conveyor. The token then waits for the red box to arrive at "DP2". The problem is that "PBInsertion" and "DP2" are located at the same spot on the conveyor. Because the pallet with the blue box is stopped at that location the red box can never get to that location. It appears that you are trying to lift the pallet and blue box up as the red box conveys underneath and then place the pallet and blue box on top of the red box. I would have the pallet and blue box exit the conveyor into a temporary queue. This way the red box can coney to the desired location. You could then move the pallet into the red box and allow the red box to resume conveying.

Even if you modified the conveyor settings to allow the objects to overlap so that the red box would arrive at "DP2". The current approach you are using would not result in the pallet being placed inside of the red box as you are not moving it inside of it (Doing this without allowing the pallet to leave the conveyor first would more than likely result in an error). Also, the later code only resumes the pallet and not the red box. So they would also not appear to be placed one on top of the other as only one would convey away from the location.

I hope this helps,

Brandon


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Amit Kulkarni avatar image Amit Kulkarni Brandon Peterson ♦ commented ·

@brandon.peterson, @joshua.s, @matt.long

I was able to solve this issue by combining suggestions from all of you. Many thanks for your help!

Amit

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