WHILE statement

This section is about the WHILE statement syntax and examples.
IMPORTANT: Input variables are not refreshed during WHILE iterations. The state change of an input variable cannot be used to describe the condition of a WHILE statement. Using an input variable in this manner might cause unexpected controller behavior.
WHILE statement properties
Item
Description
Name
WHILE ... DO ... END_WHILE
Meaning
Iteration structure for a group of ST statements.
The "continue" condition is evaluated before every iteration.
Syntax
WHILE <Boolean_expression> DO
<statement> ;
<statement> ;
...
END_WHILE ;

Example

(* ST program using WHILE statement *)

(* this program uses specific "C" functions to read characters *)
(* on a serial port *)

str := ''; (* empty string *)
nbchar := 0;

WHILE ((nbchar < 16) & ComIsReady ( )) DO
str := str + ComGetChar ( );
nbchar := nbchar + 1;
END_WHILE;
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