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Instantiation of equation

#9261  Permalink Top

Instantiation of equation

Jul-10-19 15:43:07

I am trying to model a pump system. The system consists of a controller, two ON/OFF valves, and a swept volume acting as a chamber. The controller is responsible for the state of the valves as well as filling the volume and pumping it. When connecting all the components together, i started getting errors saying " Failed to instantiate equation between components ", for example between the swept volume and the first valve. I tried to delete the valves from the whole system and connect the piston directly to the source, but i then got an error saying "Failed to instantiate equation .." between the piston displacment and its input.

I couldn't understand where is my problem to be exact. Is it with the model themselves that they cannot be connected together or am i missing something else?

I am not an expert in modelica obviously, but i got the basics of course.

To make things clearer, i attached the model.


Any help would be appreciated.


Edited by: DATA99 - Jul-10-19 15:44:42
#9268  Permalink Top

Re: Instantiation of equation

Jul-11-19 17:54:37


Hi,

in model PumpChamber  there are a lot of wrong connect(.. statements.  Remove all connects in Text View mode, reconnect and try again.

BR / johann

#9271  Permalink Top

Re: Instantiation of equation

Jul-12-19 08:07:05

Hello,

Yup, thats true. i thought like be deleting the connections directly from the diagram view, it will be directly deleted from the source code too. Thanks for the reply.
So i fixed the connections and i tried to check th model, but modelica is saying that " Check of PumpChamber completed successfully.
Class PumpChamber has 383 equation(s) and 382 variable(s).
235 of these are trivial equation(s). ",  which results in an overdetermined system. My question is that is there a way or another that i can track the missing variable or where exactly i am missing it ?


i updated the my model to be more clearer.

Edited by: DATA99 - Jul-12-19 08:31:38
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