Statement - Conditional execution of statements.

Syntax

   ON <BOOL expression> DO
        <statements>
   END_DO;

Remarks

Statements within the ON structure are executed only when the boolean expression rises from FALSE to TRUE. The ON instruction avoids systematic use of the R_TRIG function block or other "last state" flags.

The ON syntax is available in any program, sub-program or UDFB. It is available in both T5 p-code or native code compilation modes.

This statement is an extension to the standard and is not IEC61131-3 compliant.

ST Language

(* This example counts the rising edges of variable bIN *)
ON bIN DO
   diCount := diCount + 1;
END_DO;

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