检测未使用常量值定义上限的 FOR 语句
理由如果循环的上限是一个变量值，那么就无法再查看循环的执行频率。这会导致运行时出现严重问题。最坏的情况是无限循环。
重要性：高
示例
PROGRAM PLC_PRG VAR i:INT; iBorder1: INT := 10; iBorder2: INT := 10; iCounter: INT; END_VAR VAR CONSTANT ciBorder:INT := 10; END_VAR FOR i:=0 TO 10 DO //OK iCounter := i; END_FOR FOR i:=0 TO ciBorder DO // OK iCounter := i; END_FOR FOR i:=0 TO iBorder1 DO // SA0081 iCounter := i; END_FOR FOR i:=0 TO iBorder2 DO // SA0081 iCounter := i; IF iCounter = 10 THEN iBorder2 := 50; END_IF END_FOR --> SA0081: Upper border of a for loop must be a constant value