National Instruments BridgeVIEW - Manual (Page 27)

Chapter 1 Introduction
BridgeVIEW User Manual 1-4 © National Instruments Corporation
information, acknowledge alarms, view real-time trends and retrieve
historical data. For more information about how to get started with
BridgeVIEW, see the
Where Should I Start? section at the end of this
chapter.
G Programming
G is the easy-to-use graphical data flow programming language
BridgeVIEW is based upon. G simplifies scientific computation,
process monitoring and control, test and measurement, and a wide
variety of other applications.
G was first introduced by National Instruments as the programming
language behind LabVIEW, the program development application used
commonly for test and measurement purposes. BridgeVIEW has taken all
the functionality of G and enhanced it for your industrial automation needs.
The G Tutorial section of this manual covers the functionality of G that you
need to get started with most BridgeVIEW applications. For a more
extensive explanation of BridgeVIEW functionality, see the
G Programming Reference Manual.
The basic concepts of G that are covered in this manual are as follows:
• VIs—Virtual instruments (VIs) have three main parts: the front panel,
the block diagram, and the icon/connector. The front panel specifies
the user interface of the VI. The block diagram consists of the
executable code that you create using nodes, terminals, and wires.
With the icon/connector, you can use a VI as a subVI in the block
diagram of another VI. For more information about VIs, refer to
Chapter 9,
Creating VIs , and Chapter 10, Customizing VIs .
• Loops and Charts—G has two structures to repeat execution of a
sub-diagram—the While Loop and the For Loop. Both structures are
resizable boxes. You place the subdiagram to be repeated inside the
border of the loop structure. The While Loop executes as long as the
value at the conditional terminal is TRUE. The For Loop executes a set
number of times. Charts are used to display real-time trend information
to the operator. For more information about loops and charts, refer to
Chapter 11,
Loops and Charts .
• Case and Sequence Structures—The Case structure is a conditional
branching control structure, which executes a subdiagram based on
certain input.
sequence structure is a program control structure that
executes its subdiagrams in numeric order. For more information about
Case or Sequence structures, refer to Chapter 12,
Case and Sequence
Structures and the Formula Node .