In a sub VI a LED is switched on and 5 sec later the LED is switched off. How can I read the LED status in the main VI? The sub VI gives me only the end situation (LED off)
you can register a user event for this control in your main vi. Another option is to send a notification if the control value changes. The main vi should be able to react on this notification.
This'll work, too, if you don't mind polling. It fits your stated question to "read the LED status".
Jim You're entirely bonkers. But I'll tell you a secret. All the best people are. ~ Alice For he does not know what will happen; So who can tell him when it will occur? Eccl. 8:7
