Help needed with structured text

chrisk_81

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• May 14, 2011

• #1

Hi all,

I'm trying to assign the individual characters from a STRING data type to an array of BYTE's as below:

text : STRING(5) := 'hello';
char : ARRAY[0..4] OF BYTE;

Does anyone know how to get this to work? I thought this below would work but it doesn't:

char[0] := text[0];
char[1] := text[1];
char[2] := text[2];
char[3] := text[3];
char[4] := text[4];

 

Last edited: May 14, 2011

MichaelG

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• May 14, 2011

• #2

to get a better answer please tell up what PLC you are using

eg RSLogix 5000 does not have Byte data type
The STRING data type that is a system defined data type containing .LEN DINT and .DATA SINT[82] where the SINT is the contains the individual characters you are wanting to manipulate

 

chrisk_81

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• May 14, 2011

• #3

The software I'm using is cp1131 and is used to program Berghof cpu's.

I've tried accessing the characters via text.DATA[n] but cp1131 doesn't like it.

Would love to know if anyone out there has an idea on how this data might be accessed.

 

Last edited: May 14, 2011

TurpoUrpo

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• May 14, 2011

• #4

It uses Codesys 2? If so you can download oscat basic library from oscat.de and use CODE to extract chars from string.

Code:

FOR Index := 1 TO 100 DO
    Chars[i] := CODE(STR := STR, POS := i);
END_FOR;

 

MichaelG

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• May 14, 2011

• #5

Quick check on the website

http://www.berghof.com/multimedia/Downloads/BAT/Dokumente/CANtrol/Developers_Frame/CP1131/CP1131_M_HB_en.pdf

You will have to use the string functions
eg Psuedo code

Code:

CharArray :Array[1..80] of Byte;
FOR index :=  1 to LEN(text) BY 1 DO
     CharArray[index] := MID(text,1,Index);
END_for;

Cute PLC

 

TurpoUrpo

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• May 14, 2011

• #6

MichaelG said:

Quick check on the website

http://www.berghof.com/multimedia/D...ol/Developers_Frame/CP1131/CP1131_M_HB_en.pdf

You will have to use the string functions
eg Psuedo code

Code:

CharArray :Array[1..80] of Byte;
FOR index :=  1 to LEN(text) BY 1 DO
     CharArray[index] := MID(text,1,Index);
END_for;

Cute PLC

Click to expand...

This does not work. MID returns string.

 

Archie

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• May 14, 2011

• #7

Code:

VAR
 text : STRING[5]:='hello';
 char : ARRAY[0..4] OF BYTE;
 PT : POINTER TO BYTE;
 i : INT;
END_VAR
 
-------------------------------------------
 
pt:=ADR(text);
FOR i:=0 TO 4 DO
 char[i]:=pt^;
 pt:=pt+1;
END_FOR

 

chrisk_81

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• May 14, 2011

• #8

Thanks everyone for their input but Archie you are the man! That solution worked beautifully and also taught me a few things I didn't know. Thanks again for your help.