Bridge User Manual

Creating VIs

This chapter introduces the basic concepts of virtual instruments and

provides activities that explain the following:

• How to create the icon and connector

• How to use a VI as a subVI

What is a Virtual Instrument?

A virtual instrument (VI) is a program in the graphical programming

language G. Virtual instrument front panels often have a user interface

similar to physical instruments. G also has built-in functions that are similar

to VIs, but do not have front panels or block diagrams as VIs do. Function

icons always have a yellow background.

How Do You Build a VI?

One of the keys to creating BridgeVIEW applications is understanding and

using the hierarchical nature of the VI. After you create a VI, you can use

it as a subVI in the block diagram of a higher-level VI.

VI Hierarchy

When you create an application, you start at the top-level VI and define the

inputs and outputs for the application. Then, you construct subVIs to

perform the necessary operations on the data as it flows through the block

diagram. If a block diagram has a large number of icons, group them into a

lower-level VI to maintain the simplicity of the block diagram. This

modular approach makes applications easy to debug, understand, and

maintain.

As with other applications, you can save your VI to a file in a regular

directory. With G, you also can save multiple VIs in a single file called a

VI library.

Saving VIs as individual files is more effective than using VI libraries

because you can copy, rename, and delete files more easily than if you are