question

Shinya O avatar image
0 Likes"
Shinya O asked Matthew Gillespie commented

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

mfc-result.png

mfc.fsm

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

The three lines settings are followings:

  1. MassFlowExitTransfer1: Units per Package 100
  2. MassFlowExitTransfer2: Units per Package 10
  3. 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

FlexSim 21.0.6
massflowconveyor
mfc-result.png (126.1 KiB)
mfc.fsm (71.4 KiB)
· 3
5 |100000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

Felix Möhlmann avatar image Felix Möhlmann commented ·

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.

1638516274645.png

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

2 Likes 2 ·
1638516274645.png (8.8 KiB)
Shinya O avatar image Shinya O Felix Möhlmann commented ·

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 Likes 0 ·
Ryan Clark avatar image Ryan Clark commented ·

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.

0 Likes 0 ·

1 Answer

Ryan Clark avatar image
0 Likes"
Ryan Clark answered Matthew Gillespie commented
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
5 |100000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

Shinya O avatar image Shinya O commented ·

Hi @Ryan Clark ,

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

1 Like 1 ·
Joerg Vogel avatar image Joerg Vogel commented ·
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.
1 Like 1 ·
Matthew Gillespie avatar image Matthew Gillespie ♦♦ commented ·

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

1 Like 1 ·