That's not a Modelica file, but a "flat Modelica" file. They cannot be used as input to the compiler.

Ok thank you, indeed I passed directly the model file and it worked!

However, on some other models, I get a "Too few equations, under-determined system." error.

The class file output by omc indeed shows more variables than equations but my old compiler (modelicac) used to pass these models.
I compared the class file and they are roughly the same.
Is there an flag I should give to omc in order to pass, or am I doing something wrong?
I didn't forget the mass in my model.
I noticed

Thank you very much!
Paul

It might just be something that changed in the Modelica specification (modelicac does not follow recent standards). I can't really say without seeing the model in question, but you could try with --std=1.x or --std=2.x to see if that makes a difference.

Tried with std 1.x & 2.x but the errors were the same.

Here is the model:

model Switched_im
  parameter Real VA_11(fixed=false) =0.1  "VA_11";
  parameter Real f_12(fixed=false) =4000  "f_12";
  parameter Real Ron_21(fixed=false) =0.0001  "Ron_21";
  parameter Real Roff_22(fixed=false) =100000000  "Roff_22";
  parameter Real Ron_31(fixed=false) =0.0001  "Ron_31";
  parameter Real Roff_32(fixed=false) =100000000  "Roff_32";
  parameter Real C_41(fixed=false) =0.0000000001  "C_41";
  parameter Real v_42(fixed=false) =0  "v_42";
  parameter Real C_51(fixed=false) =0.0000000001  "C_51";
  parameter Real v_52(fixed=false) =0  "v_52";
  parameter Real R_61(fixed=false) =1000000  "R_61";
  parameter Real C_121(fixed=false) =0.00000000001  "C_121";
  parameter Real v_122(fixed=false) =0  "v_122";
  VsourceAC     VsourceAC1(VA=VA_11, f=f_12);
  Switch     Switch1(Ron=Ron_21, Roff=Roff_22) "Switch";
  Switch     Switch2(Ron=Ron_31, Roff=Roff_32) "Switch";
  Capacitor     Capacitor1(C=C_41, v(start=v_42)) "Capacitor";
  Capacitor     Capacitor2(C=C_51, v(start=v_52)) "Capacitor";
  Resistor     Resistor1(R=R_61) "Resistor";
  OpAmp     OpAmp1;
  OpAmp     OpAmp2;
  Ground     Ground1;
  VoltageSensor     VoltageSensor1;
  VoltageSensor     VoltageSensor2;
  Capacitor     Capacitor3(C=C_121, v(start=v_122)) "Capacitor";
  OutPutPort     OutPutPort1;
  OutPutPort     OutPutPort2;
  InPutPort     InPutPort1;
  InPutPort     InPutPort2;
equation
  connect (VoltageSensor2.n,VoltageSensor1.n);
  connect (OpAmp1.in_p,VoltageSensor1.n);
  connect (OpAmp2.in_p,VoltageSensor1.n);
  connect (Capacitor3.n,VoltageSensor1.n);
  connect (Ground1.p,VoltageSensor1.n);
  connect (VsourceAC1.p,VoltageSensor1.n);
  connect (VoltageSensor2.p,OpAmp2.out);
  connect (Capacitor2.n,OpAmp2.out);
  connect (VoltageSensor1.p,Capacitor1.n);
  connect (OpAmp1.out,Capacitor1.n);
  connect (OpAmp2.in_n,Resistor1.n);
  connect (Capacitor2.p,Resistor1.n);
  connect (OpAmp1.in_n,Switch2.n);
  connect (Capacitor1.p,Switch2.n);
  connect (Switch1.p,VsourceAC1.n);
  connect (Resistor1.p,VsourceAC1.n);
  connect (Switch2.p,Switch1.n);
  connect (Capacitor3.p,Switch1.n);
  VoltageSensor2.v = OutPutPort1.vi;
  VoltageSensor1.v = OutPutPort2.vi;
  InPutPort1.vo = Switch1.inp;
  InPutPort2.vo = Switch2.inp;
end Switched_im;

And here is the class output by omc (error: The model has 78 equation(s) and 80 variable(s)):

class Switched_im
  parameter Real VA_11(fixed = false) = 0.1 "VA_11";
  parameter Real f_12(fixed = false) = 4000.0 "f_12";
  parameter Real Ron_21(fixed = false) = 0.0001 "Ron_21";
  parameter Real Roff_22(fixed = false) = 100000000.0 "Roff_22";
  parameter Real Ron_31(fixed = false) = 0.0001 "Ron_31";
  parameter Real Roff_32(fixed = false) = 100000000.0 "Roff_32";
  parameter Real C_41(fixed = false) = 1e-10 "C_41";
  parameter Real v_42(fixed = false) = 0.0 "v_42";
  parameter Real C_51(fixed = false) = 1e-10 "C_51";
  parameter Real v_52(fixed = false) = 0.0 "v_52";
  parameter Real R_61(fixed = false) = 1000000.0 "R_61";
  parameter Real C_121(fixed = false) = 9.999999999999999e-12 "C_121";
  parameter Real v_122(fixed = false) = 0.0 "v_122";
  Real VsourceAC1.p.v;
  Real VsourceAC1.p.i;
  Real VsourceAC1.n.v;
  Real VsourceAC1.n.i;
  Real VsourceAC1.i;
  Real VsourceAC1.v;
  parameter Real VsourceAC1.VA = VA_11 "Amplitude";
  parameter Real VsourceAC1.f = f_12 "Frequency";
  parameter Real VsourceAC1.PI = 3.141592653589793;
  Real Switch1.p.v;
  Real Switch1.p.i;
  Real Switch1.n.v;
  Real Switch1.n.i;
  Real Switch1.i;
  Real Switch1.v;
  parameter Real Switch1.Ron = Ron_21 "Resistance when the Switch is closed";
  parameter Real Switch1.Roff = Roff_22 "Resistance when the switch is open";
  Real Switch1.inp;
  Real Switch1.Rx;
  Real Switch2.p.v;
  Real Switch2.p.i;
  Real Switch2.n.v;
  Real Switch2.n.i;
  Real Switch2.i;
  Real Switch2.v;
  parameter Real Switch2.Ron = Ron_31 "Resistance when the Switch is closed";
  parameter Real Switch2.Roff = Roff_32 "Resistance when the switch is open";
  Real Switch2.inp;
  Real Switch2.Rx;
  Real Capacitor1.p.v;
  Real Capacitor1.p.i;
  Real Capacitor1.n.v;
  Real Capacitor1.n.i;
  Real Capacitor1.i;
  Real Capacitor1.v(start = v_42);
  parameter Real Capacitor1.C(fixed = true) = C_41 "Capacitance";
  Real Capacitor2.p.v;
  Real Capacitor2.p.i;
  Real Capacitor2.n.v;
  Real Capacitor2.n.i;
  Real Capacitor2.i;
  Real Capacitor2.v(start = v_52);
  parameter Real Capacitor2.C(fixed = true) = C_51 "Capacitance";
  Real Resistor1.p.v;
  Real Resistor1.p.i;
  Real Resistor1.n.v;
  Real Resistor1.n.i;
  Real Resistor1.i;
  Real Resistor1.v;
  parameter Real Resistor1.R = R_61 "Resistance";
  Real OpAmp1.in_p.v;
  Real OpAmp1.in_p.i;
  Real OpAmp1.in_n.v;
  Real OpAmp1.in_n.i;
  Real OpAmp1.out.v;
  Real OpAmp1.out.i;
  Real OpAmp2.in_p.v;
  Real OpAmp2.in_p.i;
  Real OpAmp2.in_n.v;
  Real OpAmp2.in_n.i;
  Real OpAmp2.out.v;
  Real OpAmp2.out.i;
  Real Ground1.p.v;
  Real Ground1.p.i;
  Real VoltageSensor1.p.v;
  Real VoltageSensor1.p.i;
  Real VoltageSensor1.n.v;
  Real VoltageSensor1.n.i;
  Real VoltageSensor1.i;
  Real VoltageSensor1.v;
  Real VoltageSensor2.p.v;
  Real VoltageSensor2.p.i;
  Real VoltageSensor2.n.v;
  Real VoltageSensor2.n.i;
  Real VoltageSensor2.i;
  Real VoltageSensor2.v;
  Real Capacitor3.p.v;
  Real Capacitor3.p.i;
  Real Capacitor3.n.v;
  Real Capacitor3.n.i;
  Real Capacitor3.i;
  Real Capacitor3.v(start = v_122);
  parameter Real Capacitor3.C(fixed = true) = C_121 "Capacitance";
  Real OutPutPort1.vo;
  Real OutPutPort1.vi;
  Real OutPutPort2.vo;
  Real OutPutPort2.vi;
  Real InPutPort1.vo;
  Real InPutPort1.vi;
  Real InPutPort2.vo;
  Real InPutPort2.vi;
equation
  VsourceAC1.v = VsourceAC1.VA * sin(2.0 * VsourceAC1.PI * VsourceAC1.f * time);
  VsourceAC1.i = VsourceAC1.p.i;
  VsourceAC1.n.i = -VsourceAC1.i;
  VsourceAC1.v = VsourceAC1.p.v - VsourceAC1.n.v;
  Switch1.Rx * Switch1.i = Switch1.v;
  Switch1.Rx = if Switch1.inp > 0.0 then Switch1.Ron else Switch1.Roff;
  Switch1.i = Switch1.p.i;
  Switch1.n.i = -Switch1.i;
  Switch1.v = Switch1.p.v - Switch1.n.v;
  Switch2.Rx * Switch2.i = Switch2.v;
  Switch2.Rx = if Switch2.inp > 0.0 then Switch2.Ron else Switch2.Roff;
  Switch2.i = Switch2.p.i;
  Switch2.n.i = -Switch2.i;
  Switch2.v = Switch2.p.v - Switch2.n.v;
  Capacitor1.C * der(Capacitor1.v) = Capacitor1.i;
  Capacitor1.i = Capacitor1.p.i;
  Capacitor1.n.i = -Capacitor1.i;
  Capacitor1.v = Capacitor1.p.v - Capacitor1.n.v;
  Capacitor2.C * der(Capacitor2.v) = Capacitor2.i;
  Capacitor2.i = Capacitor2.p.i;
  Capacitor2.n.i = -Capacitor2.i;
  Capacitor2.v = Capacitor2.p.v - Capacitor2.n.v;
  Resistor1.R * Resistor1.i = Resistor1.v;
  Resistor1.i = Resistor1.p.i;
  Resistor1.n.i = -Resistor1.i;
  Resistor1.v = Resistor1.p.v - Resistor1.n.v;
  OpAmp1.in_p.i = 0.0;
  OpAmp1.in_n.i = 0.0;
  OpAmp1.in_p.v - OpAmp1.in_n.v = 0.0;
  OpAmp2.in_p.i = 0.0;
  OpAmp2.in_n.i = 0.0;
  OpAmp2.in_p.v - OpAmp2.in_n.v = 0.0;
  Ground1.p.v = 0.0;
  VoltageSensor1.i = 0.0;
  VoltageSensor1.i = VoltageSensor1.p.i;
  VoltageSensor1.n.i = -VoltageSensor1.i;
  VoltageSensor1.v = VoltageSensor1.p.v - VoltageSensor1.n.v;
  VoltageSensor2.i = 0.0;
  VoltageSensor2.i = VoltageSensor2.p.i;
  VoltageSensor2.n.i = -VoltageSensor2.i;
  VoltageSensor2.v = VoltageSensor2.p.v - VoltageSensor2.n.v;
  Capacitor3.C * der(Capacitor3.v) = Capacitor3.i;
  Capacitor3.i = Capacitor3.p.i;
  Capacitor3.n.i = -Capacitor3.i;
  Capacitor3.v = Capacitor3.p.v - Capacitor3.n.v;
  OutPutPort1.vi = OutPutPort1.vo;
  OutPutPort2.vi = OutPutPort2.vo;
  InPutPort1.vi = InPutPort1.vo;
  InPutPort2.vi = InPutPort2.vo;
  VoltageSensor2.v = OutPutPort1.vi;
  VoltageSensor1.v = OutPutPort2.vi;
  InPutPort1.vo = Switch1.inp;
  InPutPort2.vo = Switch2.inp;
  OpAmp1.in_p.i + OpAmp2.in_p.i + Ground1.p.i + VoltageSensor1.n.i + VoltageSensor2.n.i + VsourceAC1.p.i + Capacitor3.n.i = 0.0;
  OpAmp1.in_n.i + Switch2.n.i + Capacitor1.p.i = 0.0;
  OpAmp1.out.i + VoltageSensor1.p.i + Capacitor1.n.i = 0.0;
  OpAmp2.in_n.i + Capacitor2.p.i + Resistor1.n.i = 0.0;
  OpAmp2.out.i + VoltageSensor2.p.i + Capacitor2.n.i = 0.0;
  VsourceAC1.n.i + Switch1.p.i + Resistor1.p.i = 0.0;
  Switch1.n.i + Switch2.p.i + Capacitor3.p.i = 0.0;
  Capacitor3.n.v = Ground1.p.v;
  Capacitor3.n.v = OpAmp1.in_p.v;
  Capacitor3.n.v = OpAmp2.in_p.v;
  Capacitor3.n.v = VoltageSensor1.n.v;
  Capacitor3.n.v = VoltageSensor2.n.v;
  Capacitor3.n.v = VsourceAC1.p.v;
  Capacitor2.n.v = OpAmp2.out.v;
  Capacitor2.n.v = VoltageSensor2.p.v;
  Capacitor1.n.v = OpAmp1.out.v;
  Capacitor1.n.v = VoltageSensor1.p.v;
  Capacitor2.p.v = OpAmp2.in_n.v;
  Capacitor2.p.v = Resistor1.n.v;
  Capacitor1.p.v = OpAmp1.in_n.v;
  Capacitor1.p.v = Switch2.n.v;
  Resistor1.p.v = Switch1.p.v;
  Resistor1.p.v = VsourceAC1.n.v;
  Capacitor3.p.v = Switch1.n.v;
  Capacitor3.p.v = Switch2.p.v;
end Switched_im;

Thank you for your time,
Paul

FYI modelicac used to report when it failed, and it passed that model (simulation was correct somehow)

The model is not very useful, but I suspect modelicac allowed input variables not on the top level class to count as inputs to the simulation. InPutPort1.vi lacks an equation in your model, which is not allowed in Modelica.

Yes there seems to be a logic: the number of missing equations in the error message corresponds to the number of inputs to the model.

I'm confused about your message though because "InPutPort1.vi = InPutPort1.vo;" looks equation enough to me, when coupled with "InPutPort1.vo = Switch1.inp;", I wonder what's missing...

Anyway, would you know a way around this please? Maybe by hand-modifying the original .mo file?

Side question: I noticed the generated C code specifies "FMI 1.0", is there a way to make it 2.0 compatible?

Thanks again,
Paul

(Current) OMC generates FMI 2.0 by default as far as I remember. Look in your model closer and you see why vi is not assigned. As far as I can see, you have

// input vi

vo := vi;

inpu := vo;

Ok, you were talking about the initial .mo, yes InPutPort.vis aren't assigned.

Compilation passes for when I add "InPutPort1.vi = 0;" for each port but I'm not sure it is recommended to set that value at the beginning?
This adds the same lines to the class output...

Here is the code InPutPort code
model InPutPort
  Real vo;
  input Real vi;
equation
    vi=vo;
end InPutPort;

And the Switch code:
model Switch
  parameter Real Ron=0.01 "Resistance when the Switch is closed";
  parameter Real Roff=1e5  "Resistance when the Switch is open";
  extends TwoPin;
  Real inp,Rx;
equation
  Rx*i= v;
  Rx=if inp >0 then Ron   
              else Roff;
end Switch;

Thanks,
Paul

In order to follow the Modelica specification and define the variable to be an input (that can somehow be controlled externally):

model M

  InPutPort p(vi=r);

  input Real r;

end M;

Only inputs in the top-level model are kept. Any other input variables need to be connected. (This is a change from Modelica 2.x, in which some tools allowed these sort of models)

I see, thank you for that alternative.
I must have failed to implement it though:

model InPutPort  // Unchanged
  Real vo;
  input Real vi;
equation
    vi=vo;
end InPutPort;

partial model TwoPin  // Unchanged
    Pin p, n;
    Real i, v;
equation
    i = p.i;
    n.i = -i;
    v = p.v - n.v;
end TwoPin;

model Switch  // Made 'inp' an input and added an InPutPort. Named it 'in' because 'p' was taken by TwoPin
  parameter Real Ron=0.01 "Resistance when the Switch is closed";
  parameter Real Roff=1e5  "Resistance when the switch is open";
  extends TwoPin;
  InPutPort in(vi=inp);
  Real Rx;
  input Real inp;
equation
  Rx*i= v;
  Rx=if inp >0 then Ron
              else Roff;
end Switch;

This gives me "Error: No viable alternative near token: InPutPort", do you see what is wrong there? So I can fix all the other components!

Thank you very much,
Paul

Note: the model file hasn't changed after I changed the components, so it may be my script to generate the models that is obsolete.
Do you know what equations are missing in the model in order to pass compilation? If I change generate them, I should be good to go.

Thanks,
Paul

Any pointers please? I have made many attempts but nothing worked
Thanks,
Paul