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Worker AvailableForMediation

Valued Contributor
Valued Contributor

Hi all,

 

In the following senario I'm trying to get a worker of capcity 4 and 4 single procs. I'm trying to get the worker to pick up 1 part from each single proc before carrying them to a buffer. (i'm working with PS v13)

 

However the worker carries the parts to the buffer one at a time.

 

What i'm struiggling to understand is why the attribute "Myworker.AvailableForMediation" = false after it has picked up only 1 part and its capacity is 4 ??

 

Thanks in advance for your help.

 

Shaun

 

8 REPLIES 8

Re: Worker AvailableForMediation

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

this is because you set the buffer as destination and you set a max. waitingtime of one minute in the exit behavior carry part away.
If you want to do the loading by yourself, you need first to switch off the automatic mediation of the worker in the class library. You need only in the first machine the exit strategy carry part away. The behavior of the worker you can program in the entrance control of the workplaces. Load one part and send the worker to the next station (command goTo).

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

Re: Worker AvailableForMediation

Siemens Phenom Siemens Phenom
Siemens Phenom

In both models AGVExample2.spp and AGVExample3.spp the read-only attribute availableForMediation changes only at the beginning of the simulation.

Please note that a ReleaseControl for a TransportImporter must be added by SimTalk:

 

.MaterialFlow.SingleProc.TransportImp.ReleaseCtrl := "releasecntrl"

and the method must be

 param type: integer
?.TransportImp.releaseExporters

 

Re: Worker AvailableForMediation

Valued Contributor
Valued Contributor

Thanks Steffen, ths is exactly what i was after!

Re: Worker AvailableForMediation

Valued Contributor
Valued Contributor

Thanks Peter, however I still don't think i understand why this is neccessary. Is "releaseExporters" method supposed to change the "availableForMediation" to "true" ?

 

 

Re: Worker AvailableForMediation

Gears Phenom Gears Phenom
Gears Phenom

I noticed some things while looking into Steffens model and Peters answer (which I cannot confirm or explain at the moment). Maybe this will get too technical, so here's my summary:

I believe that AGVExample3.spp is behaving correctly in Plant13. But in Plant14 the model does NOT behave as desired (the worker will not collect 4 parts and deliver them, but put some of them back on other SingleProcs for "re-processing" and pickup other parts from that station instead).

 

Using Plant 13, the attribute does change during simulation (you can see this if you add an observer on it):

grafik.png
Interestingly, if you add an ExporterRequestControl to the Broker, you can see that the worker will request a new "job" from the Broker after dropping all parts at Buffer, and at that time, his attribute is reset to TRUE (automatically!) and he is re-assigned (immediately, if SingleProc is ready); however without the ExporterRequestControl, the observer will always claim that the attribute is false (see above), because he is immediately reassigned (automatically). So I actually believe that AGVExample3.spp is behaving correctly in Plant13 (you can also add a second production line, see attachment; note: I send the worker back to the WorkerPool after delivering his parts and made him walk faster), but maybe Peter can tell us what he meant exactly.

 

When using Plant 14, however, the model behaves differently/incorrectly! So maybe that's why Peter made his reply. The attribute is also automatically reset to true after dropping parts at Buffer, but only if the next part at SingleProc is not ready yet; else the worker will be assigned to SingleProc and availableForMediation = FALSE. This happens sometimes, because the worker will actually carry Entity:3 to SingleProc3 and drop it there (and then he will go to SingleProc2 and drop Entity:2 there). You can see this if you change the MU color after they are picked up by the worker, e.g.
He does that all the time (dropping parts that were picked up at previous stations on other stations instead at the final buffer). So in Plant14 the model does NOT behave as desired (but IMHO it behaves more as programmed by Steffen Smiley Wink )! If you add a second production line like I did, the model will even stop in a deadlock very soon.
This is how the worker moves on his first tour, e.g.:

grafik.png

Regards
Alex

___________________________________________________________
Alex Dilg, Consultant at SimPlan AG (www.SimPlan.de)
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Re: Worker AvailableForMediation

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

you are right, it doesnt work in version 14. I guess, there are some enhancements in the routing of the worker, if he carries MUs with different destinations. This behavior is dysfunctional in this case. You can fix it by adressing all MUs to the next destination.

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

Re: Worker AvailableForMediation

Siemens Phenom Siemens Phenom
Siemens Phenom

For a correct behavior of the model the MUs always must have a correct destination. In the V13 there was a bug so that the model has worked although the destination was not set correct. An goto for the worker does not override the destination of the MU.

 

In the entrance control of the workplaces first always must be set the new destination for already loaded MUs:

waituntil singleProc3.occupied
for var i := 1 to @.numMU
     @.MU(i).destination := buffer
next
singleProc3.cont.destination:=buffer
singleProc3.cont.move(@)
@.goto(workplace4)

 

Kind regards

Karola

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Re: Worker AvailableForMediation

Gears Phenom Gears Phenom
Gears Phenom

KarolaMock schrieb:

For a correct behavior of the model the MUs always must have a correct destination. In the V13 there was a bug so that the model has worked although the destination was not set correct. An goto for the worker does not override the destination of the MU.


Thanks for the clarification, that's good to know! One more reason for switching to V14 Smiley Happy

___________________________________________________________
Alex Dilg, Consultant at SimPlan AG (www.SimPlan.de)
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