How to get the correct number of Package Items from the mass flow conveyor?

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question

Shinya O asked Dec 3, '21 Matthew Gillespie commented Dec 20, '22

How to get the correct number of Package Items from the mass flow conveyor?

mfc.fsm

Here is a model consisting of mass flow conveyors, but it has a problem.

The three lines settings are followings:

MassFlowExitTransfer1: Units per Package 100
MassFlowExitTransfer2: Units per Package 10
MassFlowExitTransfer3: Units per Package 1

After running the simulation, the line from source 1 to sink 1 is fine, but the line from source 2 to sink 2 and from source 3 to sink 3 has one less sink input than expected.

There seems to be a problem with MassFlowExitTransfer.

Is there a way to get the correct number of Package Items from the mass flow conveyor?

Thanks

Software Version:

FlexSim 21.0.6

massflowconveyor

mfc-result.png (126.1 KiB)

mfc.fsm (71.4 KiB)

· 3

Felix Möhlmann commented · Dec 03, 2021 at 07:25 AM

It's probably a floating point inaccurary and/or a ">" rather than a ">=" somewhere in the code determining the output.

If I use 9.9999... for the units per package (output) or 100.0...0001 for the units per item (input), I get the correct amount of output. When using enough decimal places this shouldn't realistically make a difference for a model run.

Still, I'd be interested to hear if anyone has a better idea, so I'll post this as a comment for now.

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1638516274645.png (8.8 KiB)

Shinya O Felix Möhlmann commented · Dec 08, 2021 at 06:04 AM

Thank you for your reply.

Since using 9.9999... and 100.0...00001 is not a good way, I'd like to set enough decimal places.

Setting Decimal Precision to a large number (e.g. 20) in the Model Settings window did not solve the problem.

I've found that the calculations may not match due to floating point numbers, but is there a better way to avoid this?

0 ·

Ryan Clark commented · Dec 15, 2021 at 07:21 PM

Hi @Shinya O, was my answer helpful? If so, please click the "Accept" button at the bottom of my answer. Or if you still have questions, add a comment and we'll continue the conversation.

If we haven't heard back from you within 3 business days we'll auto-accept an answer, but you can always unaccept and comment back to reopen your question.

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Answer 1 · 2021-12-09T21:17:28Z

Ryan Clark answered Dec 9, '21 Matthew Gillespie commented Dec 20, '22

Hi @Shinya O,

This appears to be a bug with the Mass Flow Conveyors. I just submitted a dev report, so someone on the dev team will take a look at this and/or respond to this post. In the meantime, I would just use one of Felix's suggested workarounds.

I hope this helps! Best of luck!

· 3

Shinya O commented · Dec 10, 2021 at 12:33 AM

Hi @Ryan Clark ,

I hope that the bug is fixed. Thank you for your support.

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Joerg Vogel commented · Dec 10, 2021 at 07:27 AM

As long as there is a deviation and you set units per package, you can still try to transmit your data in labels to be able to get sufficient results. Then you wouldn’t depend on counting items anymore.

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Matthew Gillespie ♦♦ commented · Dec 20, 2022 at 11:46 PM

This bug has been fixed for 22.0.11 which comes out later this week.

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