National Instruments BridgeVIEW - Manual (Page 36)

Chapter 2 BridgeVIEW Environment
BridgeVIEW User Manual 2-2 © National Instruments Corporation
Virtual Instruments
VIs have both an interactive user interface and a source code equivalent,
and accept parameters from higher-level VIs. VIs have three main parts:
• The front panel
• The block diagram
• The icon/connector
With these features, G promotes and adheres to the concept of modular
programming. You divide an application into a series of tasks, which
you can divide again until a complicated application becomes a series
of simple subtasks. You build a VI to accomplish each subtask and then
combine those VIs on another block diagram to accomplish the larger task.
Finally, your top-level VI contains a collection of subVIs that represent
application functions.
Because you can execute each subVI by itself, apart from the rest of the
application, debugging is much easier. Furthermore, many low-level
subVIs often perform tasks common to several applications, so you can
develop a specialized set of subVIs and reuse them in different applications.
For more information about VIs, see Chapter 9, Creating VIs , and
Chapter 10, Customizing VIs , in this manual, or refer to the
G Programming Reference Manual.
Front Panel
VIs contain an interactive user interface, which is called the front panel,
because it simulates the panel of a physical device. The front panel can
contain knobs, push buttons, graphs, and other controls and indicators.
You input data using a keyboard, mouse, touch screen, or other device
and then view the results on the computer screen.
The front panel contains a toolbar of command buttons and status indicators
that you use for running and debugging VIs. It also contains font options
and alignment and distribution options for editing VIs. Pictures of the front
panel toolbar, and its buttons, are shown below.
Run button—Runs the VI.
Continuous Run button—Runs the VI over and over; useful for
debugging.