version r16690 works fine, thx

Ok I guess it's the version ... thanks a lot, I'll try with the new one

Cheers

My structure is:
-----------------------
package TestFMU
     model EinfachesModell (which I exported as FMU)
     model FMUimport (where I want to use the FMU)
end ...

TestFMU_EinfachesModell_me_FMU (the imported FMU file from the work directionary)
-----------------------

I plotted the output values (y) of the submodels in FMUimport. The original model (TestFMU.EinfachesModell) shows the right behaviour, but the output of the FMU (testfmu_einfachesmodell_me_fmu1.y) is zero

And I'll ask our IT to install the new version, I don't have admin rights Thanks for the tip

T

OMEdit version r16574

The Model I exported:
model EinfachesModell
  Modelica.Blocks.Interfaces.RealInput u annotation(Placement(visible = true, transformation(origin = {-97.9072,4.18562}, extent = {{-10,-10},{10,10}}, rotation = 0), iconTransformation(origin = {-97.9072,4.18562}, extent = {{-10,-10},{10,10}}, rotation = 0)));
  Modelica.Blocks.Interfaces.RealOutput y annotation(Placement(visible = true, transformation(origin = {100.455,-4.73157}, extent = {{-10,-10},{10,10}}, rotation = 0), iconTransformation(origin = {100.455,-4.73157}, extent = {{-10,-10},{10,10}}, rotation = 0)));
  Modelica.Blocks.Math.Gain gain1(k = 2) annotation(Placement(visible = true, transformation(origin = {-4.73157,2.00182}, extent = {{-10,-10},{10,10}}, rotation = 0)));
equation
  connect(gain1.y,y) annotation(Line(points = {{6.26843,2.00182},{93.5396,2.00182},{93.5396,-3.63967},{93.5396,-3.63967}}));
  connect(u,gain1.u) annotation(Line(points = {{-97.9072,4.18562},{-18.0164,4.18562},{-18.0164,2.1838},{-18.0164,2.1838}}));
end EinfachesModell;

The model where I compare the original model with the FMU import:
model FMUimport
  Modelica.Blocks.Sources.Clock clock1 annotation(Placement(visible = true, transformation(origin = {-47.8617,17.8344}, extent = {{-10,-10},{10,10}}, rotation = 0)));
  TestFMU_EinfachesModell_me_FMU testfmu_einfachesmodell_me_fmu1 annotation(Placement(visible = true, transformation(origin = {2.76625,-5.80913}, extent = {{-10,-10},{10,10}}, rotation = 0)));
  TestFMU.EinfachesModell einfachesmodell1() annotation(Placement(visible = true, transformation(origin = {6.70445,37.2928}, extent = {{-10,-10},{10,10}}, rotation = 0)));
equation
  connect(clock1.y,einfachesmodell1.u) annotation(Line(points = {{-36.8617,17.8344},{-24.5678,17.8344},{-3.08627,17.6124},{-3.08627,37.7113}}));
  connect(clock1.y,testfmu_einfachesmodell_me_fmu1.u) annotation(Line(points = {{-36.8617,17.8344},{-23.2365,17.8344},{-23.2365,1.1065},{-8.57538,1.1065},{-8.57538,1.1065}}));
end FMUimport;

The problem is that the simulation doesn't work properly. The output of the fmu-model is always zero, even though the original model from which I exported worked. Any idea there?

Hi,

I would like to export an easy model (which just multiplies by two for the beginning) as an fmu and then import it. All im OMEdit. The export seems to work, but when I import the model with the gui and drag it into another model as a submodel the parameters of the fmu are not filled.

There are
gain1_k (the parameter of my gain, which I originally set to 2)
flowInstantiate
flowParamsStart

I dont know what to fill in for the flow* parameters so I'm stuck there. I googled them, but I didn't find sufficient anwers. I also don't understand why they aren't filled in the first place, why do I have to do it manually?

Do you have an idea what I do wrong? Is it a bug?

Cheers
T

Hello,

is there a possibility for co-simulation between openmodelica and simulink? I don't have the money for commercial libraries though...

Thanks
T

Hi Modelica Community,

I am developing a simple drive train model in which, in a first step, I wanted to integrate an easy transmission block. Gears should be shiftable, inertias and losses don't matter and so I came up with this idea:

-----------------------------------------------------------------------------------
equation
  i = ecu_bus.transmission_simple_i;

  tau_a = flange_a.tau;
  tau_b = -flange_b.tau;
  phi_a = flange_a.phi;
  phi_b = flange_b.phi;
  w_a = der(phi_a);
  w_b = der(phi_b);

  w_b = w_a / i;
  tau_b = tau_a * i;
-----------------------------------------------------------------------------------

Unfortunately this system doesn't behave the way I want it to. If I shift a gear between two rotating inertias, the ratio of the in and output velocity is changed, but no forces act, which is simply wrong.

Can I fix this problem somehow? Or is is simply wrong to set the derivates of a physical state in a relation?

Thanks for any help !

Cheers,
T

sjoelund.se wrote:

radau1 is roughly implicit euler. Which version of OpenModelica (OS, revision) are you running?

1.9.0 Beta4

Is there no list with all possible solvers?

Hi,

I have a very problem with the accuracy of simulation results even though I use a very low tolerance and wondered which solver I can use in OpenModelica.
The GUI shows:
- dassl
- euler
- rungekutta
- inline-euler
- inline-rungekutta
- dasslwort
- dasslSymJac
Are there more I can use? Can I set an implicit euler e.g.?

I don't really find a documentation about the solvers I can use in Modelica, so thx for the answers in advance!
T

Hi,

I am working on a drive train model in OpenModelica and have set up the engine so far. I used the cylinder element from the examples which is used in the EngineV6.

Now it happens that every time I work in the model it takes OMedit forever to change the model. I just draw a connection between two blocks and it is knocked out for 30 seconds. I rename a model and it takes like ten minutes until I can go on working. Also the simulation takes forever. Compiling seems to be fast, like one or two minutes, Simulation takes maybe one minute, but after that (I guess post processing the results) I have to wait approximately 15 minutes even though I took only 500 result points.

Why is the program that slow? I suppose it is not the computer: Quad Core 2GHz, 8Gig Ram... Can I change the settings somewhere that it works faster? E.g. it seems the program does a model check every single time I draw a connection, can I opt that out?

Thanks in advance
T

Hello OpenModelica Community,

I would like to simulate a four cylinder row engine with modelica. For this I use the example "Modelica.Mechanics.MultiBody.Examples.Loops.EngineV6" and changed it to four cylinders with no inclination and a crank angle offset of 180 deg each (First 0, Second 540, Third 180, Fourth 360). However it turns out that the model works fine for arbitrary angle offsets other than 180 deg, but not that value itself. In that case the initial condition w(start=10) isn't recognized and the whole machine stands still.

Has anyone an idea why it doesn't work? How can I fix it?

My changes to the model:
- no gas force in "Cylinder"
- just four cylinders
- deleted "filter" and no "load2" in engine-model

Thanks for any answer
Torben

-----------------------------------------------

Ok, works fine now, I don't really know what went wrong.
Cheers