Question

这可能是一个简单的问题。但我找不到办法解决这个问题。我正在使用s功能块向我的算法输入波形信号。波形信号正在从大约2000点的文件中读取

首先我开始模拟时间等于50.然后它只读取50分。我检查了'tout'变量。这是0,1,2，...... 50

然后我将模拟时间增加到100.结果是相同的。只读50分。但是小号是0,2,4,6..50

我尝试了10000.无论我做什么，它只读取50个值，只有0,200,400,600等宽时间步。我的s功能或simulink设置有问题吗？这是c s函数文件

    /* Give S-function a name */
#define S_FUNCTION_NAME  Readip
#define S_FUNCTION_LEVEL 2

/* Include SimStruct definition and file I/O functions */
#include "simstruc.h"
#include <stdio.h>
#include <stdlib.h>

static FILE* file2;
/* Called at the beginning of the simulation */
    static void mdlInitializeSizes(SimStruct *S)

{

        ssSetNumSFcnParams(S, 0); 


   if (ssGetNumSFcnParams(S) != ssGetSFcnParamsCount(S)) {
        return;
    }
    if (!ssSetNumOutputPorts(S, 3)) return;
    ssSetNumContStates(S, 0);
    ssSetNumDiscStates(S, 0);
    ssSetOutputPortWidth(S, 0, 1);
    ssSetOutputPortDataType(S,0,DYNAMICALLY_SIZED);
    ssSetOutputPortOptimOpts(S, 0, SS_REUSABLE_AND_LOCAL);
    ssSetOutputPortWidth(S, 1, 1);
    ssSetOutputPortDataType(S,1,DYNAMICALLY_SIZED);
    ssSetOutputPortOptimOpts(S, 1, SS_REUSABLE_AND_LOCAL);
    ssSetOutputPortWidth(S, 2, 1);
    ssSetOutputPortDataType(S,2,DYNAMICALLY_SIZED);
    ssSetOutputPortOptimOpts(S, 2, SS_REUSABLE_AND_LOCAL);


       ssSetNumPWork(S,1);
        ssSetNumSampleTimes(S, 1);
    }


    /* Set sample times for the block */
    static void mdlInitializeSampleTimes(SimStruct *S)
    {
        ssSetSampleTime(S, 0, CONTINUOUS_SAMPLE_TIME);
        ssSetOffsetTime(S, 0, 0.0);
    }



        #define MDL_START  /* Change to #undef to remove function */
        #if defined(MDL_START) 
          /* Function: mdlStart ========

    ===============================================
       * Abstract:
       *    This function is called once at start of model execution. If you
       *    have states that shou

ld be initialized once, this is the place
   *    to do it.
   */
  static void mdlStart(SimStruct *S)
  {
      /*at start of model execution, open the file and store the pointer
       *in the pwork vector */
      void** pwork = ssGetPWork(S);
      FILE *datafile;

      datafile = fopen("table.data","r");
      pwork[0] =  datafile;

      }
    #endif /*  MDL_START */

/* Function: mdlOutputs =======================================================
 * Abstract:
 *    In this function, you compute the outputs of your S-function
 *    block. Generally outputs are placed in the output vector, ssGetY(S).
 */
static void mdlOutputs(SimStruct *S, int_T tid)
{
    //get pointer to the block's output signal
    real_T       *y1 = ssGetOutputPortSignal(S,0);
    real_T       *y2 = ssGetOutputPortSignal(S,1);
    real_T       *y3 = ssGetOutputPortSignal(S,2);
    char a[10];
    char b[10];
    char c[10];
    /*get pointer to array of pointers, where the first element is the address
     *of the open file */
    void** pwork = ssGetPWork(S);

/*read a floating point number and then the comma delimiter
 *store the result in y*/

fscanf(pwork[0],"%s    %s    %s",&a,&b,&c);
*y1=atof(a);
*y2=atof(b);
    *y3=atof(c);

}



/* Function: mdlTerminate =====================================================
 * Abstract:
 *    In this function, you should perform any actions that are necessary
 *    at the termination of a simulation.  For example, if memory was
 *    allocated in mdlStart, this is the place to free it.
 */
static void mdlTerminate(SimStruct *S)
{
    //close the file
    void** pwork = ssGetPWork(S);
      FILE *datafile;

      datafile = pwork[0];
      fclose(datafile);

}



/*=============================*
 * Required S-function trailer *
 *=============================*/

    #ifdef  MATLAB_MEX_FILE    /* Is this file being compiled as a MEX-file? */
    #include "simulink.c"      /* MEX-file interface mechanism */
    #else
    #include "cg_sfun.h"       /* Code generation registration function */
    #endif

Answer 1

这似乎只是一个设置问题。如果您没有为求解器指定步长，并且块不指示采样时间，则Simulink将选择默认值Simulation Time / 50。只需打开Model Configuration Parameters对话框，然后单击左侧窗格中的求解器即可。如果使用固定步长求解器，则可以显式设置步长。如果使用变步长求解器，则可以指定最大/最小步长。

此外，如果您希望专门为您的S函数指定一个离散的采样周期，那么您可能需要查看此link以确保您根据需要实施mdlInitializeSampleTimes

Answer 2

您需要使用固定步长离散解算器。将Periodic sample time constraint设置为'Unconstrined' 输入固定步长和模拟停止时间，以便获得2000步。

例如1s / step和2000s停止时间，或0.1s /步和200s停止时间。

如何在Matlab simulink中修复步数（而不是时间）

2 个答案: