S7-300 SCL program convert string DB to real DB

[JesperMP]

Is the format of the real values always 3 decimal digits, a period, 2 fraction digits and a comma ?
If that is the case you can 'simply' extract every character one by one.
something like this:

FUNCTION_BLOCK "FB_SPLITREALSTRING"

VAR
    sourcestr : STRING[72] ; //:= '123.45,123.45,123.45,123.45,123.45,123.45,123.45,123.45,123.45,123.45,123.45,123.45' ;
    sourcestr_chars AT sourcestr : ARRAY[0..73] OF CHAR ;
    strTable : ARRAY[0..11] OF STRING[7] ;
    strTable_chars AT strTable : ARRAY[0..107] OF CHAR ;
    i : INT ;
END_VAR

LABEL 
    ERROR, NORMALEXIT ;
END_LABEL ;


FOR i:= 0 TO 11 BY 1 DO
  IF NOT (sourcestr_chars[i*7 + 5] = '.') OR NOT (sourcestr_chars[i*7 + 8] = ',') THEN 
    GOTO ERROR ;
  END_IF ;
    strTable_chars[i*9 + 2] := sourcestr_chars[i*7 + 2]; 
    strTable_chars[i*9 + 3] := sourcestr_chars[i*7 + 3]; 
    strTable_chars[i*9 + 4] := sourcestr_chars[i*7 + 4]; 
    strTable_chars[i*9 + 5] := '.';
    strTable_chars[i*9 + 6] := sourcestr_chars[i*7 + 6]; 
    strTable_chars[i*9 + 7] := sourcestr_chars[i*7 + 7]; 
    strTable_chars[i*9 + 8] := ',';
END_FOR ;
GOTO NORMALEXIT ;

ERROR:  ;

NORMALEXIT:    ;
END_FUNCTION_BLOCK

This is just a rough code idea. Not tested !
Not sure if I got the character count right, but you get the idea.

 

[L D[AR2P#0.0]]

Here's an alternative using the inbuilt string handling functions:

FUNCTION_BLOCK FB67
VAR
    sourcestr : STRING[250] ;
    strTable : ARRAY[1..12] OF STRING[7] ;
    i,iPlace,iLen, P : INT ;
END_VAR
BEGIN
//load data into source string for testing
sourcestr:='100.01,200.02,300.03,400.04,500.05,600.06,700.07,800.08,900.09,1000.10,1100.11,1200.12';// end of loading test data
FOR i:= 1 TO 11 DO
  iPlace:=FIND(IN1:=sourcestr,IN2:=',');
  strTable[i]:=LEFT(IN:=sourcestr, L:=iPlace-1);
  iLen:=LEN(S:=sourcestr);
  sourcestr:=RIGHT(IN:=sourcestr, L:=(iLEN-iPlace));
END_FOR;
strTable[12]:=sourcestr;
END_FUNCTION_BLOCK

 

[L D[AR2P#0.0]]

Instance DB results:

 

[testermax]

Thank you very much for the quick reply and code examples!!

 

[khulez]

Hi, can you please show me how to do the coding in STL(S7 300), I used the P_RCV block to receive data from rs232(using a CP341 card) into DB1 string[8]. Now I need to display the value as a real value on the operator screen(HMI). Please help