Virtual instrumentation is breaking down the barriers of developing and maintaining instrumentation systems that challenge the world of test, measurement, and industrial automation. By leveraging off the latest computing technology, virtual instrumentation delivers innovative, scalable solutions that incorporate many different I/O options and maximizes code reuse-- saving you time and money.

LabVIEW is a graphical program development application developed by National Instruments in 1986 to integrate engineering tasks like;

1. interfacing computers with the instruments,
2. collecting, storing, analyzing, transmitting measured data,
3. developing program in a graphical environment,
4. providing an effective user interface.

LabVIEW delivers real solutions to the practical problems faster than any other graphical environment.

More than a software package for controlling an instrument, LabVIEW can be used to integrate GPIB and VXI for data acquisition, automation, motion control, vision,... almost everything to build a system.

The source for these figures is http://www.natinst.com/labview/product.htm and they show how widely LabVIEW is used as instrumentation and control software, by comparing to some other programming languages.

LabVIEW is a program development application, much like various commercial C/C++, FORTRAN or BASIC development systems. However, LabVIEW uses graphical programming language, G, to create programs allowing the program to be in a "Block Diagram" form. This creates excellent GUI capabilities built-in in LabVIEW programs.

The programs written in LabVIEW are called "Virtual Instruments" or VI’s due to the instrumentation-related origin . The programs created are independent of the type of machine that they are created for so programs can be transferred between different operating systems.

Additionally LabVIEW has a large set of built-in mathematical functions and graphical data visualization and data input objects typically found in data acquisition and analysis applications. You can write most of your "code" with only the mouse. If structured "properly", this "code" can pass as your flow chart.

During the last 10 years the original LabVIEW version has been enriched and refined, ported to several

platforms, accurately documented, completed with software drivers for a full line of hardware products.

Some features of LabVIEW:

• graphical programming called as "G" language,

• data-flow-controlled execution, as compared to sequential execution of text-line based languages,
• real time visual debugging features

• built in drivers and function libraries for the serial, parallel and network computer ports.

• simple file input-output operations,
• "Plug-and-play" interface devices for most types of an external equipment.
• direct program portability (binary files) between different platforms: PCs, Macintosh, Sun, HP-UX, and operating systems.
• a wealth of visual debugging tools,
• add-on software packages for specific extension of the program features, for instance image processing,
• built-in interactive graphic control and display

• database (SQL) interfacing, libraries for industrial PLCs
• ready to use analysis functions including;

• Communication (TCP, UDP, DDE, OLE, HiQ)

• signal generation (sine wave, triangle wave, square wave, sawtooth, uniform, gaussian white and periodic white noise, etc.)
• digital signal processing (FFT, power spectrum, hilbert transform, convolution, derivative x(t), integral x(t), etc.)
• measurement (power spectrum, time domain windowing, transfer function, harmonic analyzer, pulse parameters, peak detection, etc. )
• filtering (butterworth, IIR, chebyshev, bessel filter, median filter etc.)
• windows (hanning, hamming, triangle, flat top, force window, exponential window, etc.)
• curve fitting (linear, exp., poly., nonlinear Lev-Mar.fit, interpolation, etc.)
• probability and statistics functions ( mean, standard deviation, RMS, histogram, distributions (chi square, F, t, inverse distributions, erfc(x), erf(x), contingency table, etc), ANOVA (1D, 2D, 3D), etc.
• linear algebra ( many functions including some advanced linear algebra functions)
• array operations ( numerical methods, roots, etc.)

• code interface function to use DLL’s written any other language. This feature gives the opportunity to use the codes written in conventional languages (C/C++, Visual Basic, etc) to be used in a LabVIEW program.
• add-on software packages for specific extension of the program features, for instance image processing,

All of the LabVIEW functions are very easy to use. The illustration below shows an example program which is used for data acquisition.

1. control panel or front panel,
2. diagram (flow diagram).

The control panel looks exactly what you would expect from an instrument to have. The control boxes on the left of the panel are the controls (or inputs). The graph window is an indicator (output). These controls and indicators are pulled from the menu using the mouse.

The diagram window is where the connections are made. The icons on the left of the diagram windows are the representations of the inputs that we inserted into the front panel. The icons that we see in the control diagram are the functions to configure the board, start reading, and get Analog Input data functions which were pulled from the functions menu using a mouse. Then the icons are connected using a wiring tool. The icon named as "transposed voltage graph" is the representation of the graph in the front panel. The orange wire from "AI Read" to "Graph" shows the path. Any analysis would be similar icons on this path, the would be plotted similarly after the analysis.

Using LabVIEW, almost all of the instruments that are used in a lab could be simulated (saving money!).

FRONT PANEL:

BLOCK DIAGRAM WINDOW:

The program below is created by modifying one of the examples supplied with LabVIEW 4.1 software. The program generates sinusoidal signal combined with noise generated by "White noise" function and filters the signal using "Butterworth filter" function. The signal before and after filtering is plotted in the panel window, then power spectra of both signals are plotted in a similar graph.

• William D. Phillips won the 1997 Nobel Prize for physics -- he controlled his atom-cooling Experiments with LabVIEW running on a Macintosh (http://www.natinst.com/)

• Independent surveys show that LabVIEW is the answer if you're interested in shaving days, weeks, or months from your development time!

• LabVIEW is the first graphical programming language in general commercial use today.

• NIDays-Europe 97 one-day technical conferences will be held at 23 different locations across Europe during the Autumn of 1997. You can check out for the times and locations from page: http://www.natinst.com/nidays/nid_loc.htm.

• You can obtain free product information from: http://digital.natinst.com/guest.nsf/newproduct. (i.e. Instrupedia 97 CD-ROM - the interactive encyclopedia of instrumentation (Windows and Macintosh), 1998 Instrumentation and Reference Catalogue - the printed version of on-line catalog plus tutorials and glossary, Instrumentation Newsletter - quarterly newsletter on computer-based test and measurement, AutomationView Newsletter - quarterly newsletter on computer-based industrial automation, etc. )

• You can join to LabVIEW information, discussion list by sending subscription to the info-LabVIEW list maintainer at [email protected].

• Bill O’Brien, Senior Systems Engineer in Motorola, says:

probably 20 man-months in

just this one effort alone...

our productivity doubled."

-- Bill O'Brien, Senior

Systems Engineer,

Motorola Satellite

Communications Group

Ismail Cicek,

Ph.D. Student,

Mechanical Engineering Dept.

Texas Tech University,

Lubbock, TX