Controls, constants, and indicators, Controls, constants, and indicators -2 – National Instruments BridgeVIEW User Manual

Page 210

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Chapter 9

Creating VIs

BridgeVIEW User Manual

9-2

© National Instruments Corporation

using a VI library. For a list of the advantages and disadvantages of using
VI libraries and individual files, see the section Saving VIs in Chapter 2,
Editing VIs
, of the G Programming Reference Manual.

VI libraries have the same load, save, and open capabilities as other
directories. VI libraries, however, are not hierarchical. That is, you cannot
create a VI library inside of another VI library. You cannot create a new
directory inside a VI library, either. There is no way to list the VIs in a
VI library outside the BridgeVIEW environment.

After you create a VI library, it appears in the BridgeVIEW file dialog box
as a folder with VI on the folder icon. Regular directories appear as a folder
without the VI label.

Even though you might not save your own VIs in VI libraries, you should
be familiar with how they work. In the various activities in this manual, you
will save your VIs in the

BridgeVIEW\Activity

directory. Solutions to

these activities are provided in the

BridgeVIEW\Activity\Solution

directory.

Controls, Constants, and Indicators

A control is an object you place on your HMI for entering data into a VI
interactively or into a subVI programmatically. An indicator is an object
you place on your HMI for displaying output. Controls and indicators in G
are similar to input and output parameters, respectively, in traditional
programming languages. An alternative to placing controls and indicators
on the front panel and then wiring them to functions or VIs on the block
diagram, is to create controls or indicators directly from the block diagram.
To do this, pop up on the input terminal of a function or VI on the block
diagram and select Create Control. This creates a control of the correct
data type and wires it to the terminal.

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