Item entering Conveyor on trailing edge

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Sebastian Hemmann asked Oct 18, '17 Matthew Gillespie commented Oct 18, '17

Item entering Conveyor on trailing edge

Hi,

I´m looking for an easy solution for items entering conveyors on a special Position depending on the items size.

As far as I found out any Transferpoint (and Entrytransfer if it is on the start side) lets items enter Conveyors with their leading edge.

Entrytransfers positioned anywhere along the Conveyor let Items enter this Entrypoint with their Center.

But I´m looking for a solution that lets Items enter Conveyors with their trailing edge.

My idea was to take an Entrytransfer along the conveyor.

And I then tryed to set the Position of the Entrytransfer dynamicly by Code to the right Point. But this didn´t work.

My actual try is to Position a Photo Eye exactly on the same distance as the Entry Transfer Point and add an "Transfer Item" logic in the OnBlock Trigger to move item by half of it´s length allong the conveyor.

In the attached model you find a simple example but it seems as if the Photo Eyes don´t get informations about transfered Items and so the first one is even blocked after the item left:

and the second Photo Eye doesn´t recognice the items leading edge:

So does anybody have a good idea or solution how to solve it?

Maybe I´m using an completly wrong Approach!?

example-transferitemonconveyor.fsm

Software Version:

FlexSim 17.2.2

conveyor photo eye trailing edge

first-photoeye.png (171.9 KiB)

second-photoeye.png (58.2 KiB)

example-transferitemonconveyor.fsm (26.9 KiB)

Answer 1 · 2017-10-18T16:43:58Z

Joerg Vogel answered Oct 18, '17 Matthew Gillespie commented Oct 18, '17

@sebastian.hemmann, you are right it depends on the center of the item. The function which set the middle of the entrytransfer is

function_s(transfer, "setDistAlongConveyor", transferSY/2);

The variable transferSY contains the size of the entering item. I set the new position in the OnEntry trigger of a queue previous to the entrytransfer. The queue has a capacity of 1.

conveyor-trailing-edge-entry.fsm (25.8 KiB)

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Sebastian Hemmann commented · Oct 18, 2017 at 05:29 PM

Thanks again for the quick and very helpful reply Jörg. It seems not to be the first time I´m looking for an Option "function_s()" or "function_n()" is the solution for. Do you maybe have a good hint where to find any overview about that stuff? Help and even the Forum says "for development use" and gives a very small Explanation.

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Matthew Gillespie ♦♦ Sebastian Hemmann commented · Oct 18, 2017 at 06:59 PM

function_s() is a command like nodefunction(). It just executes code on a node. Specifically it looks for a node with the specified name in the eventfunctions node of the specified object. The library objects have lots of different methods on them, but we've only chosen to expose certain of them as commands or dot syntax methods. There are several reasons for not exposing a certain function on an object. One big one is that when we expose a function we are committing to maintain that option so that it continues to work (if at all possible) in future versions. Other times the function is very specific and won't be used by most users.

For now, we will sometimes point out a function_s() call when a user needs it for a specific purpose, but we don't intend to expose it for everyone or guarantee it will be maintained.

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