Allen-Bradley LOGIX 5000 Reference Manual page 531

Structured Text Programming
Structured Text
Operand Type
bool_ BOOL
expression
Important: Do not iterate within the loop too many times in a single scan.
The controller does not execute other statements in the routine until it
completes the loop.
A major fault occurs when completing the loop takes longer than the
watchdog timer for the task.
Consider using a different construct, such as IF_THEN.
Description
The syntax is:
The following diagrams show how a REPEAT_UNTIL loop executes and how an
EXIT statement leaves the loop early.
While the bool_expression is false, the controller executes only the statements
within the REPEAT_UNTIL loop.
To stop the loop before the conditions are false, use an EXIT statement.
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Format Enter
Tag expression BOOL tag or expression that evaluates to a BOOL value
(BOOL expression)
Chapter 10
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