How to deflect (and decide on this) a flowitem exactly at a conveyor junction

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David Besson asked Nov 16, '16 David Besson answered Nov 17, '16

How to deflect (and decide on this) a flowitem exactly at a conveyor junction

I need to process a flowitem exactly at the junction of a conveyor. Then, depending on the process result, the flowitem will continue on the main conveyor, or will go to the conveyor spike.

This logic (here: 100% to the spike) should produce this result (but with the second spike connected):

But it seems that when the leading edge of the flowitem had passed the center of the side transfer, this flowitem cannot be diverted to the first spike:

Am I doing wrong? How could I fix that?

Note: This related post is similar, but does not answer to my question: Link

q-conveyor-junction.fsm

Software Version:

FlexSim 16.2.2

conveyor

q-conveyor-junction.fsm (19.2 KiB)

Answer 1 · 2016-11-17T10:00:34Z

David Besson answered Nov 17, '16

I found a solution (whew!):

1): Have a first DP upstream of the branch which sends 100% of the flowitems to the branch.

2): Have a second DP at the point of the first branch which resends x% of the flowitems to the main conveyor. On this DP, the flowitems are stopped to be processed and then the decision to resend or not the flowitems is made.

In this way, it is possible to make the decision AT the point of the branch: It seems that reddirecting a flowitem (when it is at the point of the branch) to ultimately continue on the current conveyor works, while redirecting a flowitem to ultimately change conveyor is not possible.

q-conveyor-junction-2.fsm

capture3.png (49.0 KiB)

q-conveyor-junction-2.fsm (21.6 KiB)

Answer 2 · 2016-11-16T17:24:46Z

Sam Stubbs answered Nov 16, '16 David Besson commented Nov 17, '16

You do need to make sure the decision is made before the edge of the item is past the branch it is supposed to be directed down. If you NEED to have the visual of the box stopping AT the point of the first branch, one option would be to have another DP prior to that point that actually controls the decision logic, and then have the delay on the point that is adjacent to the branch.

I've included a model to demonstrate.

3766-q-conveyor-junction.fsm

3766-q-conveyor-junction.fsm (20.7 KiB)

· 1

David Besson commented · Nov 17, 2016 at 08:44 AM

Thanks for your answer.

Since I cannot make the decision before the item is at the point of the first branch and had finished its process, if I understand well there is not any solution.

To illustrate my specific case: The flowitems are processed exactly at the point of the first branch, where some of the flowitem's content is taken for a variable time. During the process, some external events may lead to take even more flowitem's content in such a way that the process will last longer. At the end of the process, if the flowitem is not empty, it will continue on the main conveyor, otherwise it is directed down.

So as I cannot predict these external events which could lead to the emptying of the flowitem, the decision could only be made at the end of the process... at the point of the first branch.

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