National Instruments BridgeVIEW 用户手册

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© National Instruments Corporation 2-1 BridgeVIEW User Manual
2
BridgeVIEW Environment
This chapter describes the BridgeVIEW environment. It explains 
the basic concepts behind G, the programming language upon which 
BridgeVIEW is built, the BridgeVIEW Engine Manager, system errors 
and events, the Tag Monitor utility, and the Tag Browser utility. This 
chapter also explains how to access online help for BridgeVIEW and 
provides an activity that illustrates how to examine the front panel 
and block diagram of a virtual instrument (VI).
What Is G?
G is a programming language, much like various commercial C or BASIC 
development languages. However, G is different from those applications 
in one important respect. Other programming languages are text-based 
languages that create lines of code, while G is a graphical programming 
language that creates programs in block diagram form.
You can use G with little programming experience. G engineers and 
programmers rely on graphical symbols and
 rather than textual 
language to describe programming actions. Data flow is a programming 
system in which nodes execute when they have received all required input 
data, and produce output automatically when they have executed.
G has extensive libraries of functions and subroutines for most 
programming tasks. BridgeVIEW includes conventional program 
development tools for G, so you can set breakpoints, animate program 
execution to see how data passes through the program, and single-step 
through the diagram to make debugging and program development easier.
How Does G Work?
G includes libraries of functions and development tools designed 
specifically for HMI development, data acquisition, and instrument 
control. G programs are calle
 because their 
appearance and operation imitate actual instruments. However, they are 
analogous to functions in conventional programming languages.