topic Re: setup time in processor when item type changes in FlexSim Forum

setup time in processor when item type changes

sara_w2 — Thu, 11 Jul 2019 17:18:34 GMT

[ FlexSim 18.1.2 ]

Hello everybody,

I have several items and a processor in my model.

The operation that I want to do is that the item comes into the processor and it will be setup during a time which depends of its Type. And I am using the option "setup If Item Type Changes (values are set)". It works perfectly for the second or third and go on items but not for the first item that come into the processor, when the first item arrives, it has not setup time and I dont know how can I fix it.

Is there any suggestion?

Thank for your attention.

Re: setup time in processor when item type changes

joseph_g3 — Thu, 11 Jul 2019 17:27:06 GMT

@Sara W2

Here's an example model that might work for you: processorsetuptime.fsm

I set the Setup Time in the processor to "Values By Case" and had the Setup Time depend on the type of the item:

Hope this helps!

Re: setup time in processor when item type changes

sara_w2 — Fri, 12 Jul 2019 17:25:49 GMT

Hi Joseph,

This option is not suitable to my case, I am seeing that this makes my system does setup to each item. I am sorry If I had not explained well my issue, I have a lot of items of several types, and my setup time should take place only once for each type when items come into the processor, it is not necessary make a setup for each item, only to the first item. Therefore, there is not setup time for the rest of items of the same type that follow.

And, thank you for your attention.

Re: setup time in processor when item type changes

joseph_g3 — Fri, 12 Jul 2019 17:32:08 GMT

@Sara W2

If I understand correctly, you would like the processor to only have a setup time for the first of each item type? Would you like the setup time to still be different based on type?

Re: setup time in processor when item type changes

joseph_g3 — Fri, 12 Jul 2019 17:40:34 GMT

@Sara W2

Also, you said that "setup If Item Type Changes" worked perfectly for you besides the first item.

Are you saying that you want a setup time every time the type changes or just the first time you encounter a certain item type?

Re: setup time in processor when item type changes

sara_w2 — Fri, 12 Jul 2019 17:51:58 GMT

For example:

I have the following queue fill of items of different types:

SINK<--PROCCESOR <-- QUEUE(x1 x2 x3 x4 x5 y1 y2 y3 y4 y5 y6 y7 z1 z2 z3 z4 w1 w2 w3 w4...)

setup time for item type X= 2 min

setup time for item type Y= 5 min

...

setup timefor item type W = 1 min

etc.

So, when x1 arrives to the processor, PROCCESOR (setup time = 2 min)

when x2 arrives, PROCCESOR (setup=0 min)

and go on.

but when y1 arrives, PROCCESOR (setup time=5 min)

when y2 arrives, PROCCESOR (setup=0 min)

and go on.

the same process will happens to z and w item types.

Re: setup time in processor when item type changes

joseph_g3 — Fri, 12 Jul 2019 18:07:09 GMT

@Sara W2

Continuing with your example, will there be repeated item types after w4?

For example:

x1 x2 x3 x4 x5 y1 y2 y3 y4 y5 y6 y7 z1 z2 z3 z4 w1 w2 w3 w4 x6 <- Would this need set up time too?

Re: setup time in processor when item type changes

sara_w2 — Fri, 12 Jul 2019 18:15:43 GMT

Yes, it could be possible. And in that case x6 would need set up time.

Re: setup time in processor when item type changes

joseph_g3 — Fri, 12 Jul 2019 18:37:55 GMT

@Sara W2

I think this is the kind of model you are looking for: setupfirstitem.fsm

It works by using the "If Item Type Changes" setup time with two changes:

1. In the slot where you specify how long the setup time should be when the item type changes, I put this:

Table("Setup Times")[item.Type][1]

This references a global table I created with setup times for each type of item (I had 5 different types). If the item type changes, it looks up the setup time in this table. If the item type is the same, there is no setup time.

2. To fix the problem of the first item having no setup time, I added a few lines of custom code to the setup time of the processor:

if(getinput(current) == 1){ //If first item
	return Table("Setup Times")[item.Type][1];
}

If the item is the first item entering the processor, it looks up the item's setup time from the global table.

I hope this helps!

Re: setup time in processor when item type changes

sara_w2 — Fri, 12 Jul 2019 20:46:16 GMT

I can't open your model, perhaps your Flexsim version is higher than mine. Could you please send me some screenshots of your model?

Re: setup time in processor when item type changes

joseph_g3 — Fri, 12 Jul 2019 20:57:08 GMT

@Sara W2

Sorry about that! Here's the same model in 18.1: setupfirstitem.fsm

Re: setup time in processor when item type changes

sara_w2 — Fri, 12 Jul 2019 21:10:45 GMT

Exactly, it is what I am looking for!

Thank you so much for the help.

Re: setup time in processor when item type changes

marcos_mna — Wed, 16 Dec 2020 17:02:23 GMT

Hi @Joseph Gillespie, if I have more than one processors, is it possible to start with the setup time once they have finished processing one type of item or they necessarily need to wait until receiving the new type of item to start their setup time?

For example, it the setup time is 200 seconds in all the processors when a change of items occurs and the time of processing of the first Processor is 100 seconds, the second Processor stay 300 seconds without doing anything instead of using this time to do their setup and to be ready to start processing the item when the item arrives to it.

Thank you!