FUNCTION_BLOCK "Avg"

VERSION : 0.1

   VAR_INPUT 

      value : Real;

      reset : Bool;

   END_VAR

   VAR_OUTPUT 

      avgValue : Real;

   END_VAR

   VAR 

      statCache : Array[0..#MAX_INDEX] of Real;

      statCacheIndex : Int;

      statIndex : Int;

      statLast : Real;

      statSum : Real;

      statAvg : Real;

   END_VAR

   VAR_TEMP 

      i : Int;

   END_VAR

   VAR CONSTANT 

      MAX_INDEX : Int := 14;

   END_VAR

BEGIN

IF #reset THEN //初始化

  FOR #i := 0 TO #MAX_INDEX DO

    #statCache[#i] := 0;

  END_FOR;

  #statCacheIndex := 0;

  #statIndex := 0;

  #statLast := 0;

  #statSum := 0;

  #statAvg := 0;

ELSIF #value <> #statLast THEN //如果值改变

  IF #statCacheIndex < #MAX_INDEX THEN //缓存未满

    #statCache[#statCacheIndex] := #value;

    #statCacheIndex += 1;

  ELSE //缓存已满

    #statCache[#statIndex] := #value;

    #statIndex += 1;

    #statIndex := #statIndex MOD #MAX_INDEX;

    #statSum := 0;

    FOR #i := 0 TO #MAX_INDEX DO

      #statSum += #statCache[#i];

    END_FOR;

    #statAvg := #statSum / #MAX_INDEX;

  END_IF;

END_IF;

#statLast := #value;

#avgValue := #statAvg;

END_FUNCTION_BLOCK

Avg.scl.zip