FUNCTION FC1 : INT

//FUNCTION Parameters

VAR_IN_OUT
PAR:UDT1;
END_VAR

VAR_OUTPUT
RELAXING:REAL;
END_VAR

VAR_TEMP
//temporary variables
I:INT;
TMAX:REAL;
TMIN:REAL;
END_VAR

//check Max
TMAX:=10.0;
FOR I:=1 TO 20 BY 1 DO
IF PAR.FILES[I].WIDTH>TMAX THEN
TMAX:=PAR.FILES[I].WIDTH;
END_IF;
END_FOR;
//check Min
TMIN:=10.0;
FOR I:=1 TO 20 BY 1 DO
IF TMIN>PAR.FILES[I].WIDTH THEN
TMIN:=PAR.FILES[I].WIDTH;
END_IF;
END_FOR;
//CALC RELAXING RATIO
RELAXING:=(TMAX/TMIN)*100.0;

FC1:=100;
END_FUNCTION


以上程序已经调试成功，非常感谢2楼的指教！