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David Chan avatar image
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David Chan asked Eric M commented

Conveyor system: Two directions

Hi! I am trying to build a conveyor system as in the model. I have a problem in moving the third piece of flowitem according to the blue arrow. May I know what was the problem?

1627993619606.png

Thanks

David

Lifer level v3.fsm

FlexSim 21.1.4
conveyorflexsim 21.1.4bi-directional
lifer-level-v3.fsm (75.3 KiB)
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Eric M avatar image Eric M commented ·

Hi @David Chan, was Jordan Johnson or anthony.johnson's answer helpful? If so, please click the red "Accept" button at the bottom of one of their answers. Or if you still have questions, add a comment and we'll continue the conversation.

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anthony.johnson avatar image
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anthony.johnson answered

https://docs.flexsim.com/en/21.2/Reference/CodingInFlexSim/FlexScriptAPIReference/Conveyor/#Property-targetSpeed

"[Reversing conveyor direction] was designed with a very specific scenario in mind, which is to give modelers the ability to simulate accumulation buffers, where items can be pulled off a main conveyor line when the line gets backed up, and then moved back onto the line when it clears out. The functionality has been tested only for this scenario. Using reversible conveyors for other scenarios has not been tested and thus may not work perfectly.

...

"No updates are made to the internal routing table when a conveyor's direction is reversed. This means, for routing purposes, i.e. when sending an item to a destination point in the system, the conveyor is always assumed to be conveying in its original direction."

Reversing conveyors was not designed for the scenario you are using. However, I was able to jury rig it to work for a single item, although there's no guarantee it will work as you scale up.

lifer-level-v3.fsm

The big thing you need to do is make sure that the conveyors' primary direction leads out of the loop. This will configure the routing table so that you can send it from somewhere in the loop to that exiting conveyor, and it will know where to go. Then, you reverse the conveyor's direction at the beginning of the simulation, so that items can get onto the loop.

The tricky thing is that you need to make sure the conveyor direction is correct at the proper times in the model: reversed when items are flowing onto loop, and normal when you are getting items off of the loop.


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Jordan Johnson avatar image
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Jordan Johnson answered David Chan commented

I don't think this scenario can work with the Conveyors in FlexSim. I think the issue is that, while conveyors can reverse directions, the routing table doesn't update when that happens. So there is no route along the blue arrow.

I think you'd need to make a second conveyor running the other direction, and send the item to that conveyor.

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Jordan Johnson avatar image Jordan Johnson ♦♦ commented ·
@anthony.johnson may know more about it.
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David Chan avatar image David Chan Jordan Johnson ♦♦ commented ·
@Jordan Johnson Looking forward to understand how this can be worked out. Thanks

David

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