Parts of VI

Parts of a VI(Virtual Instrument)

LabVIEW VIs contain three main components—the front panel window, the block diagram, and the icon/connector pane.

Front Panel Window

The front panel window is the user interface for the VI. Figure2-1 shows an example of a front panel window. You create the front panel window with controls and indicators, which are the interactive input and output terminals of the VI, respectively.

Fig.1 - VI Front Panel

Block Diagram Window

After you create the front panel window, you add code using graphical representations of functions to control the front panel objects. Figure2-2 shows an example of a block diagram window. The block diagram window contains this graphical source code. Front panel objects appear as terminals on the block diagram.

Fig.1 - VI Block Diagram

Connector and Icon Pane

The Connector and Icon pane allows you to use and view a VI in another VI. A VI that is used in another VI is called a subVI, which is similar to a function in a text-based programming language. To use a VI as a subVI, it must have an icon and a connector pane.

Fig.1 - VI Connector and Icon

To use a VI as a subVI, you need to build a connector pane, shown at left. The connector pane is a set of terminals on the icon that corresponds to the controls and indicators of that VI, similar to the parameter list of a function call in text-based programming languages. Access the connector pane by right-clicking the icon in the upper right corner of the front panel window. You cannot access the connector pane from the icon in the block diagram
window.

Every VI displays an icon in the upper right corner of the front panel window and block diagram window. An example of the default icon is shown at left. An icon is a graphical representation of a VI. The icon can contain both text and images. If you use a VI as a subVI, the icon identifie the subVI on the block diagram of the VI. The default icon contains a number that indicates how many new VIs you opened after launching LabVIEW.