modelicaopenmodelicafmipyfmi

PyFMI: Initialize parameters depending of others

I created a model in OpenModelica and would like to create a FMU from it.

Inside OpenModelica, I can initialize the parameters the following:

model r_ctrl
  parameter Real startTime(start = 0.1);
  parameter SI.Resistance u_ref(start = 230);
  parameter SI.Power p_ref(start = 1000);
  parameter Real r_start(start = u_ref*u_ref/p_ref); 
  ...

This works without any problems, during the simulation, all parameters have the values they are supposed to have

When I create the FMU, the following error appears in the terminal:

[CodegenUtil.tpl:178:14-178:14:writable] Error: Template Fehler: initial value of unknown type: r_ctrl.u_ref ^ 2.0 / r_ctrl.p_ref.

Is there a way to set the parameters dependent of each other, but without getting errors in the FMU generation process?

Solution

  • The following should work (I suppose the above should as well, but requires OpenModelica to automatically translate it into something like the following):

    model r_ctrl
  parameter Real startTime = 0.1;
  parameter SI.Resistance u_ref = 230;
  parameter SI.Power p_ref = 1000;
  parameter Real r_start(fixed=false);
initial equation
  r_start = u_ref*u_ref/p_ref;