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martin.j avatar image
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martin.j asked anthony.johnson commented

Flexsim 2021 Beta - New Mass Flow Conveyors

The new FlexSim 2021 beta is out, and I am very exited about the new Mass Flow Conveyor. We have actually considered creating something very similar using just processflow and Kinetic-TrackedVariables, but this features looks a lot more professional. Unfortunately it doesn't seem quite finished yet.

  • The drawing of the "bottles" seems a bit random. Sometimes they are drawn, othertimes they are not - resetting and running the same model multiple times generates several different results in terms of drawing.
  • Is there a way to define the diameter, color or even shape of the drawn "bottles"? I realize that they have to be very lightweight graphically, but it would be great to at least be able to alter their size and color.
  • I can't seem to get the the photo eye to trigger when blocked by full accumulation. I may be using the "Density Ratio Threshold" feature wrong, but without an updated helpfile I just can't figure it out. It appears to only trigger on bottles initally passing it, but never when the accumulation of the blocked conveyor reaches it.
  • The generation feature that creates "virtual" objects without actually spawning flow-objects in the tree under the conveyors is great, but are there any examples on how this is all meant to be used? I am imagining making machines that also use such "virtual" objects and track their production using TrackedVariable lables, but I am a bit unsure how I would go about attaching such a machine to the output of the massflow conveyor.
  • Are we likely to see further development on this feature in the comming FlexSim versions?

If it were possible to make a mass flow conveyor with photoeyes that controlled the speed of attached up- and down-stream machines and thereby controlled the accumulation level, all without using flow-item-objects, I believe one could make a truly fast packaging line simulation, despite very large product flows.

Best Regards

Martin

FlexSim 21.0.0
flexsim 21.0.0bottling module
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Lars Jacobsen avatar image Lars Jacobsen commented ·

Item 2 on your list:

You can change and add "FlowUnit" in the Toobox/Conveyor system/Mass Flow Units

and then change the FlowUnit used by the "Generative Rate".

Or you can use code to lookup a FlowUnit in the Flow Item Bin

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Ben Wilson avatar image Ben Wilson ♦♦ commented ·

@anthony.johnson

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anthony.johnson answered anthony.johnson commented
  • Random Drawing - This is a bug I've just recognized. It is manifested only in the release build of the conveyor module, hence my missing it during development.
  • Size, Shape and Color - Lars' comment is a good answer here. You use the properties of the flow unit to define size and shape. The color of the flow item bin object will determine the color it is drawn in.
  • Photo Eye Triggering - I'm attaching a test model that we use to test that the photo eye is blocking/clearing properly. Hopefully this can help you see what property settings should effect what behavior. That said, honestly we're open to suggestions as to the different modes that the photo eye should be in. The two that we came up with are a speed threshold and a density ratio threshold. I don't know the complete enumeration of what people use in real life (pressure plates, photo eyes, ...?). If your model still isn't working as you believe it should, please send us your model with an explanation of how you think it should work, and we will either fix bugs, redesign the photo eye behavior, or reply with instructions on how to get it to work the way you want.
  • Tracking Flow - The fluid content of the mass flow conveyor system is kind of a self-contained system. The statistics of the conveyors (input, output, content, loss) are automatically tracked on tracked variables of the conveyors themselves. So if you want to track these statistics, track them by attaching to/viewing those statistics on the conveyors, i.e. build the mass flow conveyor system so that you can track the statistics you need, within the system. In other words, if you want to isolate a certain flow and track that, then set the properties of the conveyors so that that flow is directed, at some point, onto a mass flow conveyor, and then track the statistics of that mass flow conveyor. That said, since you can also convert from fluid quantities to discrete quantities by attaching mass flow exit transfers to fixed resources, you can also track this flow in chunks that are represented by flow items. And finally, I'm sure there are still improvements that can be made to allow for better statistics tracking. This is our first go at it after all.
  • Further Development - We will continue to add improvements to the mass flow conveyor library. Yet I can't make any specific deadlines for when new improvements will come. Their priority will be balanced with the priorities of other feature needs in the software.

testmassflowphotoeyes.fsm (54.7 KiB)
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martin.j avatar image martin.j commented ·

Hi @anthony.johnson,

You may want to look into whether there is a bug with the photo eyes in the release build as well, because I cannot replicate your results outside the model you sent me.

If I create a mfc conveyor system with no exit, meaning that it will start to accumulate when it reaches the end, and a photoeye that responds at 0.9 density, it wont trigger when the accumulation reaches back to hit it. That only works in your model and not a new one made with the current beta build. Unless there is a very secret and sneaky trick to getting the photoeyes to function that I have not guessed.

Please see the attached model. MFC_betaTest.fsm

About the Tracking Flow; I am not so much interested in tracking the flow on a conveyor as I am interested in continuing its selfcontained fluid content on to the next machine and perhaps on to a new MFC and so forth. On a packaging line with MFCs there would be multiple stations/machines running at equally high flow rates (tens of thousands of objects per hour) and if you have to convert back to discreete flow items at these stations with the exit transfers a large part of the advantage of the fluid flow of the MFCs is lost. I have created an idea post with a feature request that would give us an interface to the fluid flow of the mfc and allow us to continue to work with tracked variables through the stations and out on to the next mfc.

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mfc-betatest.fsm (35.9 KiB)
anthony.johnson avatar image anthony.johnson ♦♦ martin.j commented ·

@martin.jensen,

Yes, it looks like this is a bug. I'll get that fixed. As far as tracking flow, I'm still not sure I see your problem. You can continue the self-contained fluid content of flow onto the next machine, just as long as the next "machine" is also a mass flow conveyor. For example, in the attached model, I simulate the operation of filler, labeler, capper, etc. "machines" by merely narrowing the flow of bottles into a set of single-lane, high-speed mass flow conveyors. I can then control those "machines" by either stopping/starting them, adjusting their speed, etc. Various "processing points" where decisions should be made, can be represented by photo eyes with decision logic on them. We just need to make sure the photo eyes give users the flexibility they need in order to do whatever is needed to be done. Perhaps we should extend the decision point to also be able to attach to mass flow conveyors, and fire a trigger every time a rate change point crosses the decision point. That would probably give the user ultimate flexibility.

TestMassFlowBottlingLine.fsm

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testmassflowbottlingline.fsm (53.3 KiB)