import headaches :: OpenModelica

import headaches

Apr-15-21 12:06:32

Hello everyone:

I started recently learning modelica, but there is a problem I avoided and I really need to solve.

I can import and simulate succesfully, both in OMEdit and through OMPython, models without units such as this:

Code:


model FirstOrder

  Real x;

equation

  der(x) = 1-x;

end FirstOrder;

But all of the following fail:

Code:


model FirstOrder

  import Modelica.Units.SI;

  SI.Position x;

equation

  der(x) = 1-x;

end FirstOrder;

Code:


model FirstOrder

  Modelica.Units.SI.Position x;

equation

  der(x) = 1-x;

end FirstOrder;

Code:

model FirstOrder

  import SI = Modelica.SIunits;

  SI.Position x;

equation

  der(x) = 1-x;

end FirstOrder;

I include both examples because of the recent change in notation in Modelica 4, since I'm not really sure if my system uses v4 or v3.2.3, since it says "Notification: Automatically loaded package Modelica 3.2.3 due to uses annotation."

I can import other libraries:

Code:

model exer

  import Modelica.Electrical.Analog.Basic;

  Basic.Resistor r(R = 10);

  Basic.Capacitor c(C = 1e-4, v(start = 0));

  Basic.Ground g;

  Modelica.Blocks.Sources.Sine sine(amplitude = 10, freqHz = 10);

  Modelica.Electrical.Analog.Sources.SignalVoltage signalVoltage1;

equation

  connect(sine.y, signalVoltage1.v);

  connect(signalVoltage1.p, r.p);

  connect(r.n, c.p);

  connect(c.n, g.p);

  connect(signalVoltage1.n, g.p);

  annotation(uses(Modelica(version="3.2.3")));

end exer;

Any idea?

Regards

Angulo: 4 Posts; Thank you [ 0 ]

#10796 Permalink

Re: import headaches

Apr-15-21 12:11:15

Change line:

Code:


annotation(uses(Modelica(version="3.2.3")));

To:

Code:


annotation(uses(Modelica(version="4.0.0")));

If you want to use Modelica 4.0.0.

adrpo: 885 Posts; Thank you [ 141 ]

#10797 Permalink

Re: import headaches

Apr-15-21 12:13:50

I forgot to ask, what OpenModelica version do you have?

adrpo: 885 Posts; Thank you [ 141 ]

#10798 Permalink

Re: import headaches

Apr-15-21 13:58:40

I got a warning recently that I could upgrade to Modelica 4.0.0, but it turns out I didn't upgrade:

> dpkg -l | grep modelica
ii drmodelica 1.17.0-1 all An OMNotebook course in the Modelica language
ii omlib-modelica-3.2.3 3.2.3~20201118~124214~git~OM~maint~3.2.3-1 all Modelica 3.2.3 is a Modelica library
ii omlib-modelicabyexample-0.5.0 0.5.0~154~g6044b75-1 all ModelicaByExample 0.5.0 is a Modelica library
ii omlib-modelicareference 20201118~124214~git~OM~maint~3.2.3-1 all ModelicaReference is a Modelica library
ii omlib-modelicaservices-3.2.3 3.2.3~20201118~124214~git~OM~maint~3.2.3-1 all ModelicaServices 3.2.3 is a Modelica library
ii openmodelica 1.17.0-1 amd64 A complete Modelica environment

Angulo: 4 Posts; Thank you [ 0 ]

#10799 Permalink

Re: import headaches

Apr-15-21 14:09:11

There you go, thanks a lot!

Code:


model FirstOrder annotation(uses(Modelica(version="3.2.3")));

  Modelica.SIunits.Position x;

equation

  der(x) = 1-x;

end FirstOrder;

Angulo: 4 Posts; Thank you [ 0 ]

#10801 Permalink

Re: import headaches

Apr-16-21 07:39:45

I would put the annotation at the end of the class. Other places in a class were removed in the Modelica 3 grammar many years ago.

sjoelund.se: 1700 Posts; Thank you [ 159 ]