Hi is there an equivalent to printf in Structured Text. I have to currently create strings by nested CONCAT statements.

Is there a better way?

Use a simple UDP protocol.

Alex

UDP - are you talking about User Datagram Protocol...can't quite see the relevance with writing several strings into a single string.

Could you elaborate???

There is no variant types in codesys so creating a real printf with placeholders like %.3f and so will be tricky.

I have made this function though that takes a input string and replaces all # characters with a value.

Note that this is written for CodeSys 3 so uses // as comments.

FUNCTION FormatString : STRING
VAR_INPUT
   Format: POINTER TO STRING;
   Value : POINTER TO STRING;
END_VAR
VAR
   CurResult: POINTER TO BYTE;
   CurValue : POINTER TO BYTE;
END_VAR
// Make a copy of the input string
FormatString:= Format^;
CurValue := Value;
CurResult:= ADR(FormatString);
WHILE (CurResult^ <> 0) AND (CurValue^ <> 0) DO
   
   // Found a placeholder (#)
   IF CurResult^ = 35 THEN
      CurResult^:= CurValue^;
      CurValue:= CurValue + 1;      
   END_IF;   
   
   CurResult:= CurResult + 1;
END_WHILE

Example:

a:= 'Hello ####';
b:= 'World';
c:= FormatString(Adr(a), Adr(b));

String c will contain "Hello World" after this.

Note that if there are more # in the format string then the value it wont replace them with spaces. It would be an idea to add code for replacing the remaining, connected # with spaces.