Problem : Conveyor Dog interval and Move flowitem conditionally

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David.Y asked Feb 14, '23 Felix Möhlmann commented Feb 16, '23

Problem : Conveyor Dog interval and Move flowitem conditionally

Hello

As always, thank you for your help.
I have a question because conveyor and control point control are not working properly.

The first question is...

It should be stopped at DP4 until 5 hangers accumulate and restart when 5 hangers accumulate in DP4

After stopping the current hanger on DP4, an attempt was made to use the event trigger with a specific hanger number or car number, but an error occurred.

You also tried to use the number in the list using the list, but it did not work.

The second question is...

The dog spacing (6m) is applied, but there is a difference in the destination point of the hanger, which can create an empty space as shown.

Is there a way to solve it?

Software Version:

FlexSim 23.0.0

conveyor control point dog interval flowitem count

1676410338596.png (360.7 KiB)

1676410354576.png (376.6 KiB)

example.fsm (11.5 MiB)

· 4

5 |100000

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

Long G commented · Feb 15, 2023 at 09:32 AM

You used English at first ,why do you change it? Problem 1 is about logic , it is easier.Problem 2 is really like a bug , dog past but didn't catch the car.

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Felix Möhlmann commented · Feb 15, 2023 at 09:47 AM

The gap happens because the second conveyor has a slightly higher speed than the first (and the third is again faster than the second). So the first conveyor can't fill its slightly higher throughput capacity.

Note: You can change the decimal precision in the model settings.

I didn't quite get your first question (possibly due to automated translation to english). Why/when would the hangers stop at DP4?

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David.Y Felix Möhlmann commented · Feb 15, 2023 at 09:55 AM

Sorry, it was translated to korean automatically,

First Question is..

It should be stopped at DP4 until 5 hangers accumulate and restart when 5 hangers accumulate in DP4

After stopping the current hanger on DP4, an attempt was made to use the event trigger with a specific hanger number or car number, but an error occurred.

You also tried to use the number in the list using the list, but it did not work.

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David.Y Felix Möhlmann commented · Feb 15, 2023 at 04:51 PM

Felix

All three conveyors have different speeds, and should be applied with the speed values in the picture.

It occurs because the input time is different at the Dog Interval (6m) interval of the conveyor when the professor's process finishes after unloading. Is there any way to solve this?

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Answer 1 · 2023-02-15T10:43:08Z

Felix Möhlmann answered Feb 15, '23 Felix Möhlmann commented Feb 16, '23

Still not 100% sure if I got it right, but here is a possible approach:

DP4 stops every arriving item. The corresponding token waits until either the hanger has arrived at the decision point or bumped up against another item on the conveyor. At that point the token pushes itself onto a list.

A separate token waits until there are at least five entries on the list and then pulls the first one, which in turn means the original token can continue and resume the hanger (once it has arrived at the decision point in case it hasn't yet, which should never happen in the current model, but better be safe :)).

DP_accumulation_fm.fsm

dp-accumulation-fm.fsm (11.5 MiB)

· 3

5 |100000

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

David.Y commented · Feb 15, 2023 at 03:57 PM

Felix, thanks a lot :)

It was close to the answer I was looking for

Unfamiliar with tokens, conveyor control and theory, I tried to do only Stop and Resume and event. As a result, 5 flow items did not wait at the DP4 point, and the conveyor where DP4 was placed stopped and all the conveyors behind it stopped at the same time, so I couldn't get the answer I wanted. Thank you.

I don't understand 100% of the logic you created, can you explain the picture below?

1. In Assign Label, Array of token.t1hanger means that t1hangers loaded with Cars are made into one group?

2. I'm not sure what the Decide logic for the meaning of event Arrive at DP4

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1676479008850.png (10.1 KiB)

David.Y commented · Feb 15, 2023 at 05:16 PM

example2.fsm

Felix Thank you so much for your help,

I just want to ask 2 more questions as I don't have enough accurate knowledge about conveyors and control points right now.

1. As shown in the video below, when the conveyor is stopped, there is a problem that the car continues to pile up with Process4.

What I want is for the cars to stop at points A to E in the BUFFER section and move forward one by one. At this time, the dog interval timing of the conveyor must match. First of all, it didn't work well when I set the Acquire Area/Release Area of the Control Point's Area restriction. Any way to solve it?

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녹화-2023-02-16-02-05-05-18.mp4 (9.9 MiB)

example2.fsm (11.5 MiB)

Felix Möhlmann David.Y commented · Feb 16, 2023 at 07:45 AM

Item gap on second conveyor:

The gap on the second conveyor is definitely caused by the speed difference. Changing the timing on the processor might delay it but you will always get a gap eventually, as long as the second conveyor runs continuously. You'd have to stop it if a dog is about to pass the entry without an item waiting to be caught. (Push waiting items to a list and have a token try to pull an item every 6m/speed seconds. If it could not pull an item immediately, stop the conveyor until it can.)

Array label:

The "t1hanger_array" label is just a copy of "t1hanger" but in the format of an array with one entry. This is needed to be able to compare the label to the "Back Slug" parameter (a reference to the items bumping against items in front) of the item bump event which is given in the form of an array.

Decide logic:

In theory an token might be pulled from the list before the respective item has actually arrived at DP4. The arrival trigger of DP4 creates the "arrived" label with a value of 1 to be able to check from the process flow if the item is already waiting at the decision point. For an explanation of the "?", see this manual page.

Processor4:

The issue is that there is nothing stopping the Process Flow unloading items onto Processor4 if it is blocked (the "Maximum Content" setting is only taken into account for port connections). You could manage this in the Process Flow via resources. The same logic would then have to be added to the other stations as well.

example2_fm.fsm

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example2-fm.fsm (11.6 MiB)

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