Moving average in WinCC

hello,

So if i understand it, the mean value can be logged in the tagarchiving. But the mean isnt the same as an moving average.So i would like to run a cyclicC action which computes my running average of a tag that i read from an OPC server.

thanks,

B Bakels

Hello,

Ive got the C-code and it is working but i still have a problem. What im doing is to create a moving average window of 15 items, this isnt working because after it hits 0 the Moving average is been reset. I think i need to fill a array.

This is the code:
#include "apdefap.h"

int gscAction( void )
{
static float movaver_old;
float movaver;
float value;
static int n;

value = GetTagFloat("input");

if (n==0) movaver = value;
else
movaver = ((movaver_old * (n-1))+value)/n;

if (n>=16) n=1;
else n++;

movaver_old = movaver;

return 0;
}

hi,
it's interesting to see your script.
I've made some changes. I hope it works.



#include "apdefap.h"

int gscAction( void )
{
static float movaver_old;
float movaver;
float value;
static int n = 1; //init the tag at the first cycle; prevent division by zero

value = GetTagFloat("input");

if (n==0) movaver = value; //it's not neccessary
else
movaver = ((movaver_old * (n-1))+value)/n;

if (n>=16) n=1; //increment only at startup , not cyclic
else n++;

movaver_old = movaver;

movaver = ((movaver_old * (n-1))+value)/n;
if (n <=16) n++;
movaver_old = movaver;
return 0;
}