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Problem with my model


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Hello,


i have some problems with my model and i really hope you can help me with that. I don't think it is too difficult but i don't know how to solve that. Please take a look at the attached model.


So the goal of my attached model is that vehicles transport entities to the servers. The vehicles should wait till they are fully loaded with 4 entities but they are not allowed to have a length which is more than 12 meters. Each entity has a certain length.

Every server has a random distributed processing time. As soon as the entity exits the server, a new entity is created. The vehicle should always pick up the next 4 entities. So my problems are:


1) The vehicle stops at Server 1 and i don't know why. But the vehicle delivers the first entity and then doesn't continue on his tour.


2) How can i measure how often the servers are idle? The problem is that the model needs to be changed after i get an entity to each server first. Because i want to measure how often the entities from the source arrive too late at the servers. But therefor each server should have one entity in their input buffer and one entity processing. Can is somehow start the simulation with two entities at each server? How can i realize that?


3) So length of each vehicle is not allowed to be over 12 meters when the vehicle picks up 4 entities. So in my opinion i should use the "Dwell only if" option. For example "StateVariable1<12" I wanted to use a state variable, so every time entity is loaded the length is add to that variable. But i don't know how to realize that.


4) I want to change the amount of the vehicles in the experiments. I did that with a property. Simio will just copy paste the same vehicle with the same abilities right?


I hope you can help me with that. Thanks a lot!

HeuristicTest.spfx

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If you look at the trace it shows you that the last thing that happens is the vehicle is waiting for its dwell time to end.

DwellTime.thumb.PNG.370bd208249bdb3b1945115ccb9d4e05.PNGYour vehicle is specified to Dwell Until Full - this applies at every node. You need to use the Dwell Only If property to specify which nodes where you want to wait for that condition. For example: Vehicle.CurrentNode==TransferNode1

DwillUntil.PNG.c8629ecf335598e461c0cd24d25c8e78.PNG

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Dear Dave,


thank you very much. I didn't know how to use the ModelTrace. Also i thought the dwell time is only for loading not for unloading. Thank you very much.

I spend some more time with my second problem, that i want to monitor how often the server are idle. Therfore i thought the vehicle should deliver to each server two entities in the first tour, like two containers for each station. So after the first tour i wanted to change the capacity, the speed and the loading time of the vehicle to get my normal settings of the simulation. To do this i used an OnRunInitialized Process which will change vehicle.currentcapacity and vehicle.desiredspeed after 10 minutes the simulation started. But i get an error. Seems like Simio can't assign the value but i don't understand where my mistake is. Maybe you can help me again with that. Thank you very much.

Unbenannt.JPG.e5685858f9e8617485fca26cc59c81f7.JPG

Unbenannt1.thumb.JPG.7273c692ec05a97c42ffe2b96a5e6b0f.JPG

HeuristicTest.spfx

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Basically i need to know hot to change the capacity of the vehicle during the simulation. I think the right expression would be something like this:

"Vehicle.RideStation.CurrentCapacity==4". But how to assign/implement that?

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Hi,


Vehicle1[1].Transporter.RideStation.CurrentCapacity


Your error is occurring because you are just referring to a vehicle in general you mast refer specifically to the vehicle in question.


Hope this helps, otherwise post a model.

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Hi willem,


thank you very much for your reply and your solution. I didn't know that i can enter for the assign step and the state variable an own expression. Because of the drop down menu i was thinking that i can only select from that. What why i was so confused and couldn't do anything with your expression. Thanks a lot for your help and effort!

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I extended the previous model a little bit because i want to measure how often the servers are idle.

I implemented that the following way: As soon as one server is idle it fires an event and all the other servers are idle too. Is one server idle, all servers have to stop working. Because you can consider it as an assembly line. And i count how often the event is fired. All servers fire the same failure event.


But i don't know how to repair the servers as soon as the idle server gets a new entity again. Because as soon as the idle server has new material the assembly line (all servers) can start working again. But i can't handle that with an add on process and an event because its only allowed to fire an repair event when it was idle before. So i don't know how to do that. I hope you can help me with that too. In the example i let the servers be repaired after 3 minutes.


And do you know if i can get a graph at the end of the simulation which shows at which time for how long the servers had a failure or were idle? Because under results i only see how often and how long they were idle but not when. Is that possible to get that information?


Thanks a lot for your support!

HeuristicTest3.spfx

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