National Instruments BridgeVIEW - Manual (Page 220)

Chapter 9 Creating VIs
BridgeVIEW User Manual 9-12 © National Instruments Corporation
4. Pop up on the thermometer and choose Data Operations»
Description…. Type in the description:
Displays simulated
temperature (deg F) measurement . Click on OK.
5. Select Show Help from the Help menu. Place the cursor on Volume
and then on Temp. You can see the descriptions you typed in appear
in the help window.
6. Save and close the VI.
End of Activity 9-2.
What is a SubVI?
A subVI is much like a subroutine in text-based programming languages.
It is a VI that is used in the block diagram of another VI.
You can use any VI that has an icon and a connector as a subVI in
another VI. In the block diagram, you select VIs to use as subVIs from
Functions»Select a VI…. Choosing this option produces a file dialog box,
from which you can select any VI in the system. If you open a VI that does
not have an icon and a connector, a blank, square box appears in the calling
VI’s block diagram. You cannot wire to this node.
A subVI is analogous to a subroutine. A subVI node is analogous to a
subroutine call. The subVI node is not the subVI itself, just as a subroutine
call statement in a program is not the subroutine itself. A block diagram that
contains several identical subVI nodes calls the same subVI several times.
Hierarchy Window
The Hierarchy window displays a graphical representation of the calling
hierarchy for all VIs in memory, including type definitions and global
variables. You use the Hierarchy window (Project»Show VI Hierarchy)
to display the dependencies of VIs by providing information on VI callers
and subVIs. This window contains a toolbar that you can use to configure
several types of settings for displayed items. The following illustration
shows an example of the VI hierarchy toolbar.