On Resource Available Change Activity

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zaetrab asked Jan 12, '24 zaetrab commented Jan 16, '24

On Resource Available Change Activity

Hi!

I have a simple simulation with an elevator that uses "On Resource Available Change" to make pallets wait for the elevator. The queue next to the elevator represents the elevator's roller conveyor, which picks up two pallets, so pallets can only enter when the elevator is in the down position.
In the "On Resource Available Change" block, "Change rule" I have "Increase to exact value" set. - value 1. If I understand correctly, when the elevator is in use the resource available value is 0 and changes to 1 when the resource is released. Everything works as it should, I only have one problem. When the elevator is in motion and I press reset simulation I get this error:
"exception: Exception caught in evaluation of /Tools/ProcessFlow/ProcessFlow/Elevator>stats/instances/ProcessFlow/resourceAvailable/onChange".

My questions are:
- Do I understand and use the "On Resource Available Change" block correctly in this case.
- Why does this error appear and is it possible to do something about it?

simple_elevator.fsm

Software Version:

FlexSim 24.0.1

wait for event exception error question

simple-elevator.fsm (54.1 KiB)

· 2

Felix Möhlmann commented · Jan 12 at 09:41 AM

As far as I can tell, there is no issue with how you build the Process Flow. I think this might be a bug. I moved this post to the bug report section and only write this as a comment, so a developer might take a look at this post.

As a workaround, you can use the "On Content Change" event instead. Meaning the tokens wait until the elevator is 'not acquired' rather than 'available' (which is the same thing in this case).

simple-elevator_1.fsm

1 ·

simple-elevator-1.fsm (53.2 KiB)

Joerg Vogel commented · Jan 14 at 08:57 AM

@zaetraB, “On resource available“ fires once a taskexecuter tasksequencequeue gets empty and there isn’t an active tasksequence. A taskexecuter has nothing more to do. A taskexecuter, which is doing a transport job but has still capacity left is not firing an “on Resource available“ event, if a change of content happens.

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Answer 1 · 2024-01-15T17:14:30Z

Jason Lightfoot answered Jan 15, '24 zaetrab commented Jan 16, '24

Note sure why this bug is happening, but can you not just use the default behavior for this without a process flow? Do you need it to take 2 every time?

simple-elevator_jl.fsm

I've sent it into the developers.

simple-elevator-jl.fsm (41.8 KiB)

· 1

zaetrab commented · Jan 16 at 11:51 AM

Main goal of that elevator was to pick up two pallets. I already have a solution to this problem without using "On Resource Available Change" activity, so I guess my problem is solved. Either way, thanks for help!

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On Resource Available Change Activity

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