REPEAT

The REPEAT statement executes a statement list and then evaluates a boolean condition to determine whether to repeat.

IEC 61131-3	Section 3.3.2.4
Support	Supported

Syntax

REPEAT
    statement_list
UNTIL expression
END_REPEAT ;

The UNTIL expression must be of type BOOL. A condition of any other type, such as an integer or a WORD, is reported as P4072.

Description

The REPEAT loop executes the statement list at least once. After each iteration, the boolean expression is evaluated. If the expression is TRUE, the loop terminates. If it is FALSE, the statement list executes again.

This is the opposite of a WHILE loop: WHILE continues while the condition is true, whereas REPEAT continues until the condition becomes true.

Example

Try it

Source

PROGRAM main
    VAR
        count : INT := 0;
    END_VAR

    REPEAT
        count := count + 1;
    UNTIL count >= 10
    END_REPEAT;
END_PROGRAM

See Also

• WHILE — pre-tested loop

• FOR — counted loop

• EXIT — break from innermost loop

• CONTINUE — next iteration of innermost loop