item size bigger than conveyor length

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question

Alessio Merlo asked Apr 5, '23 Jason Lightfoot commented Apr 13, '23

item size bigger than conveyor length

Hi community,

today I discovered that with a very specific configuration the conveyors doens't update its statistics. I attach the model to reproduce the issue (t est.fsm).

The model is very easy:

- 1 source generates 1 extra size item;

- 1 conveyor long enough for the extra item;

- 1 conveyor shorter than the item;

- 1 sink;

You can note that the longer conveyor updates the input/output statistics, the shorter one no.

I suppose that the conveyor system computes the item position based on the item center. Then in my case the center doesn't reach the shorter conveyor because the item reaches the ExitTransfer before.

I don't know if it is a bug or the conveyor works as designed. I open the discussion (dev team is involved too @Phil BoBo , @Jordan Johnson , @anthony.johnson ).

PS: I have already found a workaround and I place a photoeye to catch the item.

Software Version:

FlexSim 22.0.16

conveyor

test.fsm (37.9 KiB)

· 3

Jason Lightfoot ♦ commented · Apr 06, 2023 at 07:07 PM

You can also use the exit transfer stats.

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Alessio Merlo Jason Lightfoot ♦ commented · Apr 13, 2023 at 07:07 AM

Thanks @ jason! Good idea, but I don't trust the conveyor transfer, I usually delete and restore connection and I lose any reference to the transfer.

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Jason Lightfoot ♦ Alessio Merlo commented · Apr 13, 2023 at 08:22 AM

Understood - it's just the last inObject of the object you're connecting to, if that helps.

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Answer 1 · 2023-04-12T17:04:50Z

Kavika F answered Apr 12, '23 Alessio Merlo commented Apr 13, '23

Hey @Alessio Merlo, thanks for your inquiry. Flowitems are "in" a conveyor if their center is within that section of conveyor (like you deduced). Once the center crosses over to another section of conveyor, the tree will change so the flowitem switches which parent treenode it is under (i.e., which conveyor it is in). Those conveyor statistics are based on the treenodes.

The reason we don't measure by flowitem edge is because a flowitem could straddle two conveyors (or more) and suddenly your WIP has increased without an increase in items. If two conveyors say they have Input of one but there is only one flowitem, many stats will get messed up. Additionally, in a real life situation, you would use a photo eye to measure these statistics anyway.

So, like you've found, the correct method of handling Conveyor statistics is using a photo eye.

· 1

Alessio Merlo commented · Apr 13, 2023 at 07:05 AM

Thanks @ kavika to confirm my idea!

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