Rockwell-automation Logix5000 Controllers Structured Text Programming Manual do Utilizador descarregar pdf (Página 33)

Publication 1756-PM007D-EN-P - November 2012 33

Program Structured Text Chapter 1

Example 2:

If you want this Enter this structured text

Move ASCII characters from a SINT array into a string tag. (In

a SINT array, each element holds one character.) Stop when

you reach the carriage return.

1. Initialize Element_number to 0.

2. Count the number of elements in SINT_array (array that

contains the ASCII characters) and store the result in

SINT_array_size (DINT tag).

3. If the character at SINT_array[element_number] = 13

(decimal value of the carriage return), then stop.

4. Set String_tag[element_number] = the character at

SINT_array[element_number].

5. Add 1 to element_number. This lets the controller check

the next character in SINT_array.

6. Set the Length member of String_tag = element_number.

(This records the number of characters in String_tag so

far.)

7. If element_number = SINT_array_size, then stop. (You are

at the end of the array and it does not contain a carriage

return.)

8. Go to 3.

element_number := 0;

SIZE(SINT_array, 0, SINT_array_size);

While SINT_array[element_number] <> 13 do

String_tag.DATA[element_number] :=

SINT_array[element_number];

element_number := element_number + 1;

String_tag.LEN := element_number;

If element_number = SINT_array_size then

exit;

end_if;

end_while;

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Rockwell-automation Logix5000 Controllers Structured Text Programming Manual do Utilizador Página 33