Siemens SCL String assignment

[cjd1965]

Hi
I am playing around with SCL & Strings, what is the problem with the string assignment

VAR_TEMP
MyString : STRING[20] ;
END_VAR

MyString :='Hello' ; <<<<---------

I get the message illegal parameter assignment error in the compiler

Cheers

 

[cjd1965]

Got it working thanks

 

[TurpoUrpo]

So what was the reason?

 

[cjd1965]

So what was the reason?

Hi I was premature to say it was working. I stripped down the bit above and it did compile. Now I have the 'full code' it does not. I am trying to compare an input string with a constant string and return true if they match


FUNCTION FC100 : Void
VAR_INPUT
NewString : STRING[20] ;
END_VAR
VAR_TEMP
MyString : STRING[20] ;
END_VAR
VAR_OUTPUT
Result : BOOL ;
END_VAR
MyString := 'hello' ;
Result := FALSE ;
IF NewString = MyString THEN
Result := TRUE ;
END_IF ;

;
END_FUNCTION

I get error of 'assignment error' with the cursor on line of Result:=TRUE ;

 

[L D[AR2P#0.0]]

You have to copy the input parameter string to a temp before the comparison.

FUNCTION FC100 : Void
VAR_INPUT
NewString : STRING[20] ;
END_VAR
VAR_TEMP
MyString2:STRING[20]; 
MyString : STRING[20] ;
END_VAR
VAR_OUTPUT
Result : BOOL ; 
END_VAR
MyString := 'hello' ; 
MyString2:=NewString;
Result := FALSE ; 
IF MyString2 = MyString THEN 
Result := TRUE ; 
END_IF ;
;
END_FUNCTION

 

[cjd1965]

Hi thanks.

Not very intuitive.