CLAD User Interface & Event Handling Flashcards

In LabVIEW, what is the difference between a 'Notify' event and a 'Filter' event?

Answer: Filter events occur before the action and can be discarded; notify events occur after the action is complete

Filter events (with '?') fire before the action occurs allowing interception, while Notify events fire after the action is already applied to the control.

Which LabVIEW front panel element is best suited for selecting one option from a small, fixed list displayed as buttons?

Answer: Ring control

A Ring control displays a set of labeled choices as a drop-down and returns a numeric index, making it ideal for selecting one item from a short predefined list.

What is the function of the 'Stacked Sequence Structure' in LabVIEW user interface design?

Answer: Executes frames sequentially, one at a time, and shares data through sequence locals

The Stacked Sequence Structure runs each frame in order, and sequence locals pass data from one frame to subsequent frames, enforcing execution order.

How can you make a LabVIEW subVI's front panel appear when it is called from another VI?

Answer: Enable 'Show Front Panel When Called' in the VI's properties

The 'Show Front Panel When Called' option in VI Properties causes the subVI's front panel to open automatically whenever the subVI is invoked.

What is a Tab Control in LabVIEW used for?

Answer: Organizing front panel controls into multiple pages to reduce visual clutter

A Tab Control groups controls and indicators into labeled pages (tabs), allowing a complex front panel to be organized into logical sections without increasing window size.

In the Event Structure, what is the purpose of the 'Timeout' event case?

Answer: It executes when no other event occurs within the specified timeout duration

The Timeout event case runs if no registered event occurs within the timeout interval wired to the Event Structure, allowing periodic background tasks to execute.