You must not extend "ModelicaReference...ExternalObject". External objects extend from "ExternalObject".

Thanks for your quick reply.

I deleted "extends ModelicaReference.Classes.ExternalObject;" in class MyController, but without success.
Still I get the error: "Looking for a function MyController but found a class."

Do you have another idea?

You shouldn't have deleted the entire line, just changed it to "extends ExternalObject;"

Sorry for my missunderstanding.

Now I have another problem about the input arguments of my C-Code:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include "Regler3.h"

void* RegelungInit( double pgain, double igain, double dTime, MyController * p )
{
    p->i_anteil = 0.0;
    p->pgain = pgain;
    p->igain = igain;
    p->dTime = dTime;
    return(NULL);
}

void* RegelungExit( MyController * p )
{
    return(NULL);
}

double Regler3( double target, double current, MyController * p )
{
    p->error = (target - current);
    p->p_anteil = p->error * p->pgain;
    p->i_anteil += (p->igain * p->error * p->dTime);
    p->out = p->p_anteil + p->i_anteil;

    return (p->out);
}

The Header:

typedef struct
{
    double error;
    double p_anteil;
    double pgain;
    double igain;
    double out;
    double i_anteil;
    double dTime;
} MyController;


void* RegelungInit(double pgain, double igain, double dTime, MyController * p );
void* RegelungExit( MyController * p);
double Regler3(double target, double current, MyController * p );


Obviously, I have to fit the headers. They have to have the same arguments as the functions in Modelica.

The Problem is, that I don't know how to make sure that the C-Code works, when I change the functions like this, because of the structure I use in all the C-functions:

void* RegelungInit( double pgain, double igain, double dTime );
void* RegelungExit();
double Regler3( double target, double current );


Sorry I am no expert at C-Code

Well, you shouldn't need any include in the constructor or destructor (this makes OpenModelica tool automatically generate the header, which uses void*).

The constructor/destructors should be:

void* RegelungInit( double pgain, double igain, double dTime ) 

{ 

   MyController *p = (MyController*) malloc(sizeof(MyController));

    p->i_anteil = 0.0; 

    p->pgain = pgain; 

    p->igain = igain; 

    p->dTime = dTime; 

    return p; 

} 



void RegelungExit( MyController * p ) 

{ 

  free(p);

} 

Thanks for your help.
I did it a little bit diffrent, but now everything works fine.