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Setting independent equip times

Valued Contributor
Valued Contributor

Hi everyone,

 

I have a little problem with my equip settings.

 

All my robots cleaned every 2 hours. This I implemented very easily.

I took the method constant set the time and the interval. That's it. Works perfect.

 

Now the more tricky part and I have no idea how to implement.

 

I have different fault times for every robot and when they appear is totally different. But if I implement them they always appear to the same time but this is not correct.

I think I choose the wrong method but actually I have no idea which of all these methods does do what I want them to do ....

The faults should appear independently from the other robots and can appear at any time.

What I have is a total time of default times.

 

I hope you understand what I mean.

 

Thanks for your help.

Best regards,

IceTea

9 REPLIES 9

Re: Setting independent equip times

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

this behavior is very important, if you setup your model

to get the failures in different times, select in the eventcontroller --> tools --> increment variant on reset

Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Setting independent equip times

Valued Contributor
Valued Contributor

Sorry I thinks its a bit misunderstood because my topic is not that correct.

 

I have the time and the rate how often the robot has a failure and I have to implement that into my simulation.

But I can't find a method where I can combine these values.

Because if I do it manually than the robots have the failure always at the same time and often all together and that's wrong...

I hope this is more clear.

 

Best regards,

IceTea

 

Re: Setting independent equip times

Siemens Phenom Siemens Phenom
Siemens Phenom
Plant Simulation generates pseudo random numbers, thus it´s made sure to have a reproducible environment for developing the model and the chance (other then in reality) to analyse the influence of single parameter changes (even if you try to run the same experiment again in the real world, it will not be possible, because of different breakdowns, different worker mood, ...). In order to get reliable results you must run a number of experiments with different random number variants (see Steffen_Bs post). The most convenient way to do so is the ExperimentManager. It will allow you a statement like "With 95 % (confidence level - value of your choice) the result (parameter of your choice, i.e. Throughput) will be within this confidence interval (marked by lower and upper value). Expectation value is xyz (mathematically the mean value)." Statements like "Throughput will be xyz!" are definitely wrong, as soon as stochastic influences are given (which is mostly the case).

Regards

Always consider using the AttributeExplorer!

Re: Setting independent equip times

Valued Contributor
Valued Contributor

I'm not sure if I understood right...

 

Do you want to tell me that a calculation of the throughputtime is not possible?

And also it is not possible to include variable failure times?

 

 

Re: Setting independent equip times

Siemens Phenom Siemens Phenom
Siemens Phenom
both is possible for sure, no idea where the confusion is coming from ... probably I didn´t understand the question ... sorry!

Regards

Always consider using the AttributeExplorer!

Re: Setting independent equip times

Valued Contributor
Valued Contributor

Ok I will try to explain again.

 

First I need to notice the cycle time of my producution.

For that I tried to take the time by using the method StatNumIn at the begining of the line and StatNumOut at the end.

I wantet to subtract them at the end for getting the cycle time but the problem is some of my Items go through within 10min but this is not possible because I have robots with a processing time of more than 10 min.

 

And secound some of them have failure times these I cannot include variable just by setting a fix time (like the failure appears every 2hours)

 

And I tried a lot of mehtods but no one gave me the right solution for non of the two problems...

Re: Setting independent equip times

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor
do you mean cycle time or dwell time?
It is impossible to calculate times using the attributes StatNumIn.

The dwelltime you can calculate in the drain with
eventController.simTime - @.creationTime

To calculate the cycleTime you need to calculate the distances between the parts in the drain. Btw. the drain itself calculates the average cycletime --> see statAvgExitInterval
Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Setting independent equip times

Gears Phenom Gears Phenom
Gears Phenom

Regarding the failures: I assume that you used the first two input fields in the failure dialog (Start/Stop with constant distribution), judging from your description. Why not use failure profiles with MTTR and availability instead? This way all your robots will have independent failure/downtimes, and not all at the same time (--> random failures). 

grafik.png

And if you only have the parameters average failure duration (MTTR) and average time between failures (MTBF), you can calculate the availability = MTBF / (MTTR + MTBF).

Regards
Alex

___________________________________________________________
Alex Dilg, Consultant at SimPlan AG (www.SimPlan.de)
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Re: Setting independent equip times

Valued Contributor
Valued Contributor

Hey Alex,

thanks for the solution, works perfect!