REPEAT Statement

The REPEAT statement is an iteration structure for a group of Structured Text (ST) statements. The "continue" condition is evaluated AFTER any iteration
REPEAT Statement
Name
REPEAT ... UNTIL ... END_REPEAT
Syntax
REPEAT

<statement> ;

<statement> ;

...

UNTIL <Boolean_condition>

END_REPEAT ;
IMPORTANT: Because the virtual machine is a synchronous system, input variables are not refreshed during REPEAT iterations. The change of state of an input variable cannot be used to describe the ending condition of a REPEAT statement.
Example
(* ST program using REPEAT statement *)

(* this program uses specific "C" functions to read characters *)

(* on a serial port *)

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

nbchar := 0;

IF ComIsReady ( ) THEN

REPEAT

str := str + ComGetChar ( );

nbchar := nbchar + 1;

UNTIL ( (nbchar >= 16) OR NOT (ComIsReady ( )) )

END_REPEAT;

END_IF;
To insert a REPEAT statement
  • From the
    Toolbox
    , drag the
    REPEAT
     element into the language container.
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