Getting Started with LabVIEW
Contents
1. tree eerie rede pedes 5 2 Alliance Programs sss acce fice tette eme bete en xe eit eed 5 2 Appendix A System Requirements Appendix B Technical Support Resources Glossary Getting Started with LabVIEW vi www ni com Introduction to LabVIEW Refer to Appendix A System Requirements for more information about system configuration requirements Refer to the LabVIEW Release Notes for installation instructions What Is LabVIEW LabVIEW is a graphical programming language that uses icons instead of lines of text to create applications In contrast to text based programming languages where instructions determine program execution LabVIEW uses dataflow programming where data determine execution In LabVIEW you build a user interface by using a set of tools and objects The user interface is known as the front panel You then add code using graphical representations of functions to control the front panel objects The block diagram contains this code If organized properly the block diagram resembles a flowchart You can purchase several add on software toolsets for developing specialized applications All the toolsets integrate seamlessly in LabVIEW Refer to the National Instruments Web site at www ni com labview for more information about these toolsets LabVIEW is integrated fully for communication with hardware such as GPIB VXI PXI RS 232 RS 485 and plug in data acquisition devices LabV2. but you will correct that in Step 7 2 9 Getting Started with LabVIEW Chapter 2 Virtual Instruments The orange square on the While Loop is a data exit terminal called a tunnel Right click the tunnel and select Enable Indexing from the shortcut menu to allow the While Loop to collect the data and pass it to the Mean VI as a cumulative data set when the loop terminates The broken wires change to solid orange wires because the terminals are now of the same data type The block diagram should now match the following illustration gt Untitled 1 Diagram ait Until Next ms Multiple Return to the front panel and click the Run button to run the VI When you click the Stop button you see the mean of the data and the Choose file to write dialog box prompts you for the name of the file for saving the random number data points Type data txt and click the Save button Because the Mean VI is outside the While Loop the VI does not display the mean until you click the Stop button Use any text editor to open data txt and view the data B Note You can find the solution to this activity in LabVIEW vi lib tutorial 1llb Random Number Getting Started with LabVIEW Example Solution vi 2 10 www ni com Measurement This chapter teaches you some basics on how to use LabVIEW to configure communicate with and acquire data from special purpose instruments and general purpose data acquisition DAQ hardware Refer t
3. push buttons dials and other input devices Indicators are graphs LEDs and other displays Controls simulate instrument input devices and supply data to the block diagram of the VI Indicators simulate instrument output devices and display data the block diagram acquires or generates Block Diagram After you build the front panel you add code using graphical representations of functions to control the front panel objects The block diagram contains this graphical source code Front panel objects appear as terminals on the block diagram You cannot delete a terminal from the block diagram The terminal disappears only after you delete its corresponding object on the front panel Every control or indicator on the front panel has a corresponding terminal on the block diagram Additionally the block diagram contains functions and structures from built in LabVIEW VI libraries Wires connect each of the nodes on the block diagram including control and indicator terminals functions and structures Palettes LabVIEW palettes give you the options you need to create and edit the front panel and block diagram Tools Palette The Tools palette is available on the front panel and the block diagram A tool is a special operating mode of the mouse cursor When you select a tool the cursor icon changes to the tool icon Use the tools to operate and modify front panel and block diagram objects National Instruments Corporation 1 3 Getting
4. MB of swap space storage You need between 65 MB to 150 MB of disk storage space depending on the components you install LabVIEW uses a directory for storing temporary files Some of the temporary files are large so keep several megabytes of disk space available for this temporary directory The default for the temporary directory is tmp You can change the temporary directory by selecting Tools Options If LabVIEW aborts unexpectedly it might leave files behind in the temporary directory Remove old files occasionally to avoid depleting your disk space To save space install only the VIs you plan to use LabVIEW does not require a specific graphical user interface GUI such as Motif or OpenLook because LabVIEW uses X1ib to create its own GUI Getting Started with LabVIEW A 2 www ni com Appendix A System Requirements Media and System Platform Requirements Important Notes Sun LabVIEW runs on SPARCstations with Solaris 2 5 1 or later HP UX LabVIEW runs on HP workstations limit the size of a process Hewlett Packard such as LabVIEW to 64 MB You may need Model 9000 Series 700 to increase this setting to accommodate your computers with HP UX LabVIEW application Refer to the HP UX 10 20 or later section of the LabVIEW Release Notes under the Installation section for more information about changing this setting Linux LabVIEW runs on Linux for Requires GNU C Librar
5. RISK OF BODILY INJURY AND DEATH SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE TO AVOID DAMAGE INJURY OR DEATH THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES INCLUDING BUT NOT LIMITED TO BACK UP OR SHUT DOWN MECHANISMS BECAUSE EACH END USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION INCLUDING WITHOUT LIMITATION THE APPROPRIATE DESIGN PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION Conventions bold italic monospace Platform right click The following conventions are used in this manual The symbol leads you through nested menu items and dialog box options to a final action The sequence File Page Setup Options directs you to pull down the File menu select the Page Setup item and select Options from the last dialog box This icon denotes a tip which alerts you to advisory information This icon denotes a note which alerts you to important information Bold text d
6. Started with LabVIEW Chapter 1 Getting Started with LabVIEW Introduction to LabVIEW Select Window Show Tools Palette to display the Tools palette You can place the Tools palette anywhere on the screen Tools Sae ie e Controls Palette The Controls palette is available only on the front panel The Controls palette contains the front panel controls and indicators you use to create the user interface Select Window Show Controls Palette or right click the front panel workspace to display the Controls palette You can place the Controls palette anywhere on the screen gt Controls r oo aan 1 4 www ni com Chapter 1 Introduction to LabVIEW Functions Palette The Functions palette is available only on the block diagram The Functions palette contains the objects you use to program your VI such as arithmetic instrument I O file I O and data acquisition operations Select Window Show Functions Palette or right click the block diagram workspace to display the Functions palette You can place the Functions palette anywhere on the screen Functions National Instruments Corporation 1 5 Getting Started with LabVIEW Chapter 1 Introduction to LabVIEW Navigating the Controls and Functions Palettes Use the navigation buttons on the Controls and Functions palettes to navigate and search for controls VIs and functions When you click a subpalette icon the entire palette chan
7. diagram consists of executable icons called nodes and wires that carry data between the nodes The block diagram is the source code for the VI The block diagram resides in the block diagram window of the VI Terminal of a While Loop that contains a Boolean value that determines if the VI performs another iteration Front panel object for entering data to a VI interactively or to a subVI programmatically such as a knob push button or dial Palette that contains front panel controls indicators and decorative objects Utility that guides you through naming and configuring DAQ analog and digital channels Available in the Data Neighborhood of Measurement amp Automation Explorer Windows or DAQ Channel Wizard Macintosh Utility that guides you through specifying your DAQ application and it provides a custom DAQ solution Programming system that consists of executable nodes that execute only when they receive all required input data and produce output automatically when they execute LabVIEW is a dataflow system Option that allows you to build a set of data to be released at the termination of a While Loop With indexing disabled a While Loop releases only the final data point generated within the loop Getting Started with LabVIEW Glossary execution highlighting F front panel function Functions palette G General Purpose Interface Bus IEEE 488 2 indicator L Labeling tool LabVIEW MB Gett
8. function of a physical instrument Single interface library for controlling GPIB VXI RS 232 and other types of instruments VME eXtensions for Instrumentation bus Indicator that plots data points at a certain rate Loop structure that repeats a section of code until a condition is met Data path between nodes Section of wire that contains all the wire segments from junction to junction terminal to junction or terminal to terminal if there are no junctions between Point where three or more wire segments join Single horizontal or vertical piece of wire Tool to define data paths between terminals G 4 www ni com
9. with LabVIEW Debugging This chapter teaches you how to use some of the debugging techniques available in LabVIEW Use Execution Highlighting Execution highlighting traces the data flow of a VI during execution You can complete this activity in approximately 5 minutes 1 Open the Random Number Example VI you created earlier from LabVIEWNvi libNtutorial llb 2 View the block diagram and click the Highlight Execution button on the toolbar 3 Run the VI from the block diagram window The program executes in slow motion with moving bubbles to highlight the flow of execution It also displays data as it becomes available in the VI Click the Abort button to stop the VI 5 Click the Highlight Execution button again to turn off execution highlighting Ex le Single Step with Probes You can set breakpoints in a VI and single step into out of and over sections of the block diagram You also can insert probes to examine data values in detail during program execution This example shows how to insert probes and single step through a VI to monitor data while the VI runs You can complete this activity in approximately 5 minutes 1 Open the Random Number Example VI you created earlier from LabVIEWNvi libNtutorial llb National Instruments Corporation 4 1 Getting Started with LabVIEW Chapter 4 Debugging m Getting Started with LabVIEW Right click the output wire of the Random Number fun
10. IEW also has built in features for connecting your application to the Internet using the LabVIEW web server and software standards such as TCP IP networking and ActiveX Using LabVIEW you can create 32 bit compiled applications that give you the fast execution speeds needed for custom data acquisition test measurement and control solutions You also can create stand alone executables and shared libraries like DLLs because LabVIEW is a true 32 bit compiler LabVIEW contains comprehensive libraries for data collection analysis presentation and storage LabVIEW also includes traditional program development tools You can set breakpoints animate program execution National Instruments Corporation 1 1 Getting Started with LabVIEW Chapter 1 Introduction to LabVIEW and single step through the program to make debugging and development easier LabVIEW also provides numerous mechanisms for connecting to external code or software through DLLs shared libraries ActiveX and more In addition numerous add on tools are available for a variety of application needs Why Should Use LabVIEW LabVIEW empowers you to build your own solutions for scientific and engineering systems LabVIEW gives you the flexibility and performance of a powerful programming language without the associated difficulty and complexity LabVIEW gives thousands of successful users a faster way to program instrumentation data acquisition and control system
11. ITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunctions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Copyright Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instr
12. NATIONAL INSTRUMENTS LabV Getting Started with LabVIEW instr ONAL July 2000 Edition INSTRUMENTS Part Number 01 Worldwide Technical Support and Product Information www ni com National Instruments Corporate Headquarters 11500 North Mopac Expressway Austin Texas 78759 3504 USA Tel 512 794 0100 Worldwide Offices Australia 03 9879 5166 Austria 0662 45 79 90 0 Belgium 02 757 00 20 Brazil 011 284 5011 Canada Calgary 403 274 9391 Canada Ontario 905 785 0085 Canada Qu bec 514 694 8521 China 0755 3904939 Denmark 45 76 26 00 Finland 09 725 725 11 France 01 48 14 24 24 Germany 089 741 31 30 Greece 30 1 42 96 427 Hong Kong 2645 3186 India 91805275406 Israel 03 6120092 Italy 02 413091 Japan 03 5472 2970 Korea 02 596 7456 Mexico D F 5 280 7625 Mexico Monterrey 8 357 7695 Netherlands 0348 433466 New Zealand 09 914 0488 Norway 32 27 73 00 Poland 0 22 528 94 06 Portugal 351 1 726 9011 Singapore 2265886 Spain 91 640 0085 Sweden 08 587 895 00 Switzerland 056 200 51 51 Taiwan 02 2528 7227 United Kingdom 01635 523545 For further support information see the Technical Support Resources appendix To comment on the documentation send e mail to techpubs ni com Copyright 1997 2000 National Instruments Corporation All rights reserved Important Information Warranty The media on which you receive National Instruments software are warranted not to fail to execute programming instructi
13. agram nodes include functions structures and subVIs Tool to enter data into controls and operate them Display of icons that represent possible options Tool to move and resize objects Debugging feature for checking intermediate values in a VI PCI eXtensions for Instrumentation A modular computer based instrumentation platform Recommended Standard 232 a serial interface bus standard Recommended Standard 485 a serial interface bus standard Option within the DAQ Solution Wizard in which you can select from numerous categories of common DAQ applications Program control element such as a Sequence Structure Case structure For Loop or While Loop A palette contained in an icon of another palette VI used in the block diagram of another VI Comparable to a subroutine Getting Started with LabVIEW Glossary T terminal tip strip Tools palette tunnel VI virtual instrument VISA VXI W waveform chart While Loop wire wire branch wire junction wire segment Wiring tool Getting Started with LabVIEW Object or region on a node through which data pass Small yellow text banners that identify the terminal name and make it easier to identify terminals for wiring Palette that contains tools you can use to edit and debug front panel and block diagram objects Data entry or exit terminal on a structure See virtual instrument Program in LabVIEW that models the appearance and
14. ata acquisition DAQ hardware If you use only stand alone instruments and control them with GPIB VXI or serial standards refer to the Instrument I O section of this chapter Refer to Part II DAQ Basics of the LabVIEW Measurements Manual for more information about data acquisition in LabVIEW hy Note Data acquisition and the DAQ wizards are available on Windows and Macintosh only Getting Started with LabVIEW 3 2 www ni com Chapter 3 Measurement You will learn to do the following e Use the DAQ Solution Wizard to generate solutions for data acquisition applications Use the DAQ Channel Wizard to configure an analog input channel A Generate a solution from the Solutions Gallery Add analog input to the VI you created in Chapter 2 Virtual Instruments Note Refer to your hardware manual or the NI DAQ Help file for data acquisition hardware installation and configuration instructions Using the DAQ Solution Wizard If you are using DAQ hardware you must configure analog input analog output digital input or digital output channels You can launch the DAQ Channel Wizard from the DAQ Solution Wizard to configure the channels Then you can generate a DAQ solution from the Solutions Gallery On Windows you access the DAQ Channel Wizard through the Data Neighborhood in Measurement amp Automation Explorer On Macintosh you can access the DAQ Channel Wizard by selecting Tools Data Acquisition DAQ Channel Wiza
15. ction and select Probe from the shortcut menu A small number window displays the value of the data at that point Click the Step Into button on the toolbar The While Loop now flashes to indicate that the VI is running in single step mode Click the Step Into button again The Random Number function now flashes Click the Step Over button to step over the Random Number function The Random Number function executes so the output now appears in the probe Using Step Into and Step Over buttons single step a few more times through the loop to view each random number as the VI generates them Click the Pause button to run the VI in normal mode VIew the front panel and click the Stop button to stop the VI Save the collected data to data txt 4 2 www ni com Where to Go from Here This chapter describes how to use the LabVIEW Help and the additional resources available to you Refer to the LabVIEW User Manual the LabVIEW Measurements Manual or the LabVIEW Help for more information about LabVIEW programming iy Note The LabVIEW documentation set is available in Portable Document Format PDF on the LabVIEW CD in the manuals directory You must have Adobe Acrobat Reader 3 0 or later installed to view these files Online Help All built in LabVIEW VIs and functions include a complete description of the VI functionality and parameters Access context sensitive VI and function help by selecting Help Show Context Help or p
16. e Random Plot indicator and type 0 0 to change the scale Double click 10 0 on the Y axis of the Random Plot indicator and type 1 0 to change the scale The front panel should now match the following illustration 2 3 Getting Started with LabVIEW Chapter 2 Virtual Instruments stop Random Plot STOP 1 0 0 8 0 6 a a iz 0 4 Ba o 0 0 Build the Block Diagram So far you have defined how the user interface will look Now you can create the source code on the block diagram For this VI you generate random numbers ranging from zero to one and plot them on a chart You can complete this section in approximately 5 minutes 1 View the block diagram by selecting Window Show Diagram or clicking the block diagram window Tip Use the keyboard shortcut lt Ctrl E gt to switch between the front panel and block diagram 2 Thetwo terminals on the block diagram correspond to the Stop button and the Random Plot waveform chart on the front panel Select Window Show Functions Palette to show the Functions palette 3 Select Functions Numeric Random Number 0 1 As you drag the Random Number 0 1 function close to the Random Plot terminal LabVIEW automatically draws a wire When you release the mouse button to place the function LabVIEW automatically connects the function to the terminal with a wire Getting Started with LabVIEW 2 4 www ni com Chapter 2 Virtual Instruments Use the Up nav
17. ean vi and place the VI on the block diagram outside the While Loop Note It is important to place the Mean VI outside the While Loop because you want to compute the data mean only after the While Loop completes collecting the data Use the Wiring tool to right click the mean terminal on the upper right side of the Mean VI and select Create Indicator from the shortcut menu to create a numeric indicator on the front panel to display the mean of the random data Select Functions File I O Write To Spreadsheet File vi and place the VI on the block diagram outside the While Loop Use the Wiring tool to create a wire branch connecting the Random Number function and the X input terminal of the Mean VI Click the existing wire segment between the Random Number function and the Random Plot terminal Connect this wire to the X input terminal of the Mean VI The broken wire segment indicates that you are trying to wire terminals of different data types You will correct the broken wires in Step 7 0 Tip The wire segment blinks when the Wiring tool is positioned over it 6 National Instruments Corporation Create another wire branch from the branch you created in the previous step Wire this new branch from the segment outside the loop to the 1D data input of the Write to Spreadsheet File VI You use the 1D data input because the While Loop creates a one dimensional row of data from the generated random numbers The wires will be broken
18. enotes items that you must select or click on in the software such as menu items and dialog box options Bold text also denotes palette and parameter names Italic text denotes variables emphasis a cross reference or an introduction to a key concept This font also denotes text that is a placeholder for a word or value that you must supply Text in this font denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs subprograms subroutines device names functions operations variables filenames and extensions and code excerpts Text in this font denotes a specific platform and indicates that the text following it applies only to that platform Macintosh Press lt Command gt click to perform the same action as a right click Contents Chapter 1 Introduction to LabVIEW What Is EabVIEW shit et ed et be et didis 1 1 Why Should I Use LabVIEW ececssssesesecseseceecsesecseceecnecsessessecaeeeeeseeaeceseeeeaeees 1 2 How Does LabVIEW ust ce ee ree ie erts 1 2 Front Panel ioseph AR he a eee eee 1 3 Block Diagram eurer eea tein t RR e ERG RE 1 3 Palettes oeste ORE ERREUR METRI I REESE run 1 3 Tools Palette ee ea vectis 1 3 Controls Pa lette sien pp Ree ee doter ree e dae 1 4 Functions P l tte eie det ee 1 5 Navigating the Cont
19. ers and class registration System Integration If you have time constraints limited in house technical resources or other dilemmas you may prefer to employ consulting or system integration services You can rely on the expertise available through our worldwide network of Alliance Program members To find out more about our Alliance system integration solutions visit the System Integration section of www ni com National Instruments Corporation B 1 Getting Started with LabVIEW Appendix B Technical Support Resources Worldwide Support National Instruments has offices located around the world to help address your support needs You can access our branch office Web sites from the Worldwide Offices section of www ni com Branch office web sites provide up to date contact information support phone numbers e mail addresses and current events If you have searched the technical support resources on our Web site and still cannot find the answers you need contact your local office or National Instruments corporate Phone numbers for our worldwide offices are listed at the front of this manual Getting Started with LabVIEW B 2 www ni com Glossary block diagram conditional terminal control Controls palette D DAQ Channel Wizard DAQ Solution Wizard data flow E Enable Indexing National Instruments Corporation G 1 Pictorial description or representation of a program or algorithm The block
20. ges to the subpalette you selected You also can right click a VI icon on the palette and select Open VI from the shortcut menu to open the VI The Controls and Functions palettes contain the following navigation buttons e Up Takes you up one level in the palette hierarchy e Search Changes the palette to search mode In search mode you can perform text based searches to locate controls VIs or functions in the palettes FE e Options Opens the Function Browser Options dialog box from which you can configure the appearance of the palettes Data Flow LabVIEW follows a dataflow model for running VIs A block diagram node executes when all its inputs are available When a node completes execution it supplies data to its output terminals and passes the output data to the next node in the dataflow path Ss ont m 581 gt e gt gt E gt Del 10 00 pst E gt E gt 1L 10 00 Getting Started with LabVIEW 1 6 www ni com Chapter 1 Introduction to LabVIEW Where Do Start If you are new to LabVIEW use this Getting Started with LabVIEW manual and the LabVIEW Tutorial to help you get started quickly The LabVIEW Tutorial introduces you to the LabVIEW environment Getting Started with LabVIEW teaches you how to build VIs for data acquisition and instrument control and how to debug them It also teaches you how to use the Search Examples feature and the DAQ Solution W
21. he DAQ Channel Wizard helps you configure analog and digital channels by name so you can use those names in your program The DAQ Channel Wizard also conditions those channels so signal conditioning such as scaling factors and cold junction compensation are performed transparently Select Analog Input as the channel type to configure and click the Next button You also can configure analog output and digital input output in the DAQ Channel Wizard Type a channel name and channel description in the appropriate text boxes Click the Next button to continue Select the type of sensor If the channel is a temperature measurement click the check box Click the Next button to continue Define the physical quantity that you are measuring Select the units for your measurement and enter the range for the signal in the appropriate boxes Click the Next button to continue Define how the sensor scales the signal from the physical units to the hardware units Click the Next button to continue Select the data acquisition device and channel settings If you have multiple DAQ hardware devices installed choose the device that will read this signal Click the Finish button to configure the analog input channel Notice that the new configuration is listed under Data Neighborhood Windows as shown below or in the main DAQ Channel Wizard view Macintosh You have finished configuring an analog input channel for your DAQ hardware Select File Clo
22. i libNtutorial llb 2 View the block diagram Right click the Random Number function and select Replace Data Acquisition Analog Input AI Sample Channel to replace the Random Number function with the AI Sample Channel VI Be sure to select the AI Sample Channel VI and not the AI Sample Channels VI Note that the output has changed from a double precision number to a waveform This allows timing information to flow to the chart for display 3 Use the Wiring tool to right click the channel 0 input of the AI Sample Channel VI and select Create Constant from the shortcut menu to specify the name of the channel from which you will acquire data Getting Started with LabVIEW 3 6 www ni com Chapter 3 Measurement 4 Select the name of the channel you already configured in the DAQ Channel Wizard from the pull down menu on the constant 5 View the front panel Right click the graph and select Y Scale AutoScale Y from the shortcut menu 6 Click the Run button to acquire and display data on the chart Click the Stop button to stop the VI In the file dialog box enter a name such as data txt and click the Save button to save the data to a spreadsheet file 9 Save this VI as Acquire Data vi in labviewNvi libNtutorial llb Refer to the LabVIEW Measurements Manual for information about multiple point acquisition waveform generation digital I O and counter timer applications National Instruments Corporation 3 7 Getting Started
23. igation button on the Functions palette to navigate ES back to the main Functions palette 4 Create a While Loop by selecting Functions Structures While Loop The While Loop runs all code within its boundaries until the conditional terminal receives a TRUE or FALSE value The default behavior is Continue if True 5 Place the mouse cursor in the position on the block diagram where you want to anchor the top left corner of the While Loop Drag the dotted rectangle diagonally to enclose the Random Number function the Random Plot chart and the Stop button terminal The block diagram should now match the following illustration S Untitled 1 Diagram EE e i bali Random Number 0 1 Wire and Run the VI You transfer data between block diagram objects through wires Wires are different colors styles and thicknesses depending on their data types A broken wire appears as a dashed black line When you finish wiring this VI you can run it from the front panel to see it plot data to the chart You can complete this section in approximately 5 minutes 1 Select Window Show Tools Palette to show the Tools palette Select the Wiring tool on the Tools palette National Instruments Corporation 2 5 Getting Started with LabVIEW Chapter 2 Virtual Instruments 2 Wire the Stop button terminal to the While Loop conditional terminal To do this click the Stop button terminal move the mouse cursor to the conditional termi
24. ing Started with LabVIEW Debugging technique that animates VI execution to illustrate the data flow in the VI Interactive user interface of a VI Front panel apperance imitates physical instruments such as oscilloscopes and multimeters Built in execution element comparable to an operator function or statement in a text based programming language Palette that contains VIs functions block diagram structures and constants GPIB synonymous with HP IB The standard bus used for controlling electronic instruments with a computer Also called IEEE 488 bus because it is defined by ANSI IEEE Standards 488 1978 488 1 1987 and 488 2 1992 Institute of Electrical and Electronic Engineers Standard 488 2 1987 which defines the GPIB Front panel object that displays output such as a graph or LED Tool to create labels and enter text into text windows Laboratory Virtual Instrument Engineering Workbench LabVIEW is a graphical programming language that uses icons instead of lines of text to create programs Megabytes of memory 1 MB is equal to 1 024 KB G 2 www ni com node 0 Operating tool P palette Positioning tool probe PXI RS 232 RS 485 Solutions Gallery structure subpalette subVI National Instruments Corporation G 3 Glossary Program execution element Nodes are analogous to statements operators functions and subroutines in text based programming languages On a block di
25. izard You can complete the activities in this book in approximately 90 minutes LabVIEW Tutorial Use this tutorial to learn basic LabVIEW concepts The tutorial guides you through several activities to familiarize you with graphical programming Access the LabVIEW Tutorial by selecting Help Contents and Index or by clicking the LabVIEW Tutorial button in the LabVIEW dialog box shown in the following illustration You can complete the LabVIEW Tutorial in approximately 15 minutes p gt LabVIEW uick Tip National Instruments offers several toolkits that expand LabVIEW capabilities Consult the National Instruments web site www ni com or catalog for more information Do not show this window when launching National Instruments Corporation 1 7 Getting Started with LabVIEW Chapter 1 Introduction to LabVIEW Either launch LabVIEW or close all open VIs if you are already running LabVIEW to access the LabVIEW dialog box After you finish the LabVIEW Tutorial continue with the activities in this manual to learn how to build LabVIEW programs for instrument I O data acquisition and control You should complete the activities in this book in the order in which they appear because subsequent activities build on the sample programs you create Approximate completion times are given for each activity and each section within an activity Getting Started with LabVIEW 1 8 www ni com Virtual Instruments This chapte
26. k 3 or later and Microsoft Internet Explorer 4 0 or later installed Windows ME For information on using LabVIEW in Windows ME refer to www ni com windowsme National Instruments Corporation A 1 Getting Started with LabVIEW Appendix A System Requirements System 7 6 1 or later You need a minimum of 32 MB of RAM and at least 100 MB of disk storage space for the minimal installation of LabVIEW or 250 MB for the full installation Media and System Platform Requirements Important Notes Power Macintosh LabVIEW requires National Instruments recommends that you have at least 32 MB of RAM You might need more memory depending on the size of the application you design in LabVIEW and the amount of data that your application manipulates For more accurate timing install the Apple QuickTime extension When you use QuickTime timing accuracy should increase from 16 6 ms resolution to approximately 1 ms resolution System response varies depending on background applications other extensions networking activity and disk caching The LabVIEW Tutorial requires a sound card a video card capable of playing avi files and a minimum color palette setting of 256 colors with a screen resolution of 1024 x 768 pixels 16 bit color is recommended All UNIX Versions LabVIEW requires an X Window System server such as OpenWindows HP VUE CDE or X11R6 You need a minimum of 32 MB of RAM with 32
27. nal to create a wire and click again to connect the wire When you position the Wiring tool over a terminal the terminal blinks and a tip strip with the name of the terminal appears 3 Because this VI uses a Stop button you must change the behavior of the While Loop conditional terminal to Stop if True Right click the conditional terminal or the border of the While Loop and select Stop if True The appearance of the conditional terminal changes as shown at left The block diagram should now match the following illustration Untitled 1 Diagiam _ Bel x e 9 eicere e Random Number 0 1 Ii 4 View the front panel by pressing lt Ctrl E gt Select Window Show Tools Palette to show the Tools palette Select the Operating tool on the Tools palette Getting Started with LabVIEW 2 6 www ni com Chapter 2 Virtual Instruments E 5 Click the Run button on the toolbar to run the VI The front panel a should now resemble the following illustration Untitled 1 mW i TN Vil I ih In nh 6 Click the Stop button to stop the VI National Instruments Corporation 2 7 Getting Started with LabVIEW Chapter 2 Virtual Instruments Add Timing to the VI You can add a timing delay to the VI to plot the points more slowly on the waveform chart You can complete this section in approximately 5 minutes 1 View the block diagram by pressi
28. ng lt Ctrl E gt On the block diagram select Functions Time amp Dialog Wait Until Next ms Multiple and place the function inside the While Loop 2 Usethe Wiring tool to right click the millisecond multiple terminal on the left side of the Wait Until Next ms Multiple function and select Create Constant from the shortcut menu 3 250 in the millisecond multiple constant to create a 250 ms delay between the generation of points to plot for the chart The block diagram should now match the following illustration gt Untitled 1 Diagram tei m albeit le Random Number 0 1 Random Ploti is 4 Onthe front panel use the Operating tool to click the Run button to run the VI and observe the delay effect Select File Save As and save this VI as Random Number Example vi in labviewNvi libNtutorial llb Getting Started with LabVIEW 2 8 www ni com Chapter 2 Virtual Instruments Add Analysis and File 1 0 to the VI You can average the random data points you have collected and save the data to a spreadsheet file You can complete this section in approximately 10 minutes 1 View the block diagram window of the Random Number Example VI you created If the VI is not already open select File Open and browse to the Random Number Example VI in labview vi lib tutorial 11b Select Window Show Functions Palette to show the Functions palette Select Functions Mathematics Probability and Statistics M
29. ntrolling GPIB VXI RS 232 and other types of instruments Drivers using VISA are scalable across instrument I O interfaces National Instruments Corporation 3 1 Getting Started with LabVIEW Chapter 3 Measurement Refer to Part IV Instrument Control in LabVIEW of the LabVIEW Measurements Manual for more information about instrument control instrument drivers and using VISA to communicate with instruments Run the Demo Scope VI If you do not have instrument I O hardware installed run the Demo Scope VI The Demo Scope VI is the demonstration equivalent of a Getting Started VI for an actual instrument driver You can complete this activity in approximately 5 minutes 1 Open the Demo Scope VI instrument driver in LabVIEWNvi libN tutorial llb 2 Runthe program to acquire simulated data on one or two channels on the oscilloscope Change the Time Base and Volts Division settings to see the effects 3 Click the STOP F4 button to stop the VI 4 View the block diagram Notice that Initialize is called first followed by the commands to send to the instrument in the Application Example VI The Close VI then closes communication with the instrument When you program with LabVIEW drivers follow this model to initialize the instrument then call the functions to control the instrument and finally close the instrument for communication Data Acquisition This section teaches you how to use LabVIEW with general purpose d
30. o the National Instruments Developer Zone at zone ni com which offers measurement and automation resources including examples technical presentations instrument drivers and tutorial information Also refer to the LabVIEW Measurements Manual for more information about how to take and analyze measurements in LabVIEW Instrument 1 0 This section introduces you to the basic concepts on how to use LabVIEW to acquire data from instruments controlled by GPIB VXI RS 232 and other hardware standards This section also shows you how to run the Demo Scope VI if you do not have instrument I O hardware installed LabVIEW communicates with most instruments through instrument drivers which are libraries of VIs that control programmable instruments LabVIEW instrument drivers simplify instrument control and reduce test development time by eliminating the need to learn the low level programming protocol for each instrument Instruments obey a set of commands to respond to remote control and requests for data When you use LabVIEW instrument drivers you run intuitive high level command VIs such as the Read DC Voltage VI for a digital multimeter or the Configure Time Axis VI for a digital oscilloscope The driver VI you call automatically sends the appropriate instrument specific command strings to the instrument The foundation for LabVIEW drivers is the VISA Virtual Instrument Software Architecture VI library a single interface library for co
31. olution National Instruments Corporation 3 5 Getting Started with LabVIEW Chapter 3 Measurement ag 7 Click the Open Solution button to generate the solution 8 Click the Run button to take data from the configured analog input channel and log the data to a file A file dialog box prompts you for a file name Type data txt and click the Save button 9 Click the STOP button in the lower right corner of the front panel to stop the VI Use any text editor to view data txt Tip Youcan customize the front panel and block diagram of the VI solution and save your customized solutions Adding Analog 10 Save any changes you want to keep and close this VI 11 View the DAQ Solution Wizard window and click theBack button to browse other gallery categories and common solution VIs 12 Click the Cancel button to exit the DAQ Solution Wizard Input to the VI The Random Number Example VI you created in Chapter 2 Virtual Instruments generates random numbers and plots them to a chart Now you will replace the random number generator with an analog input VI to acquire data from your DAQ device plot it on a chart analyze it and write it to a file You can complete this activity in approximately 5 minutes hy Note If you have not built the Random Number Example VI you can find the solution VI in LabVII EWNvi libNtutorial llbNRandom Number Example Solution vi 1 Open the Random Number Example VI from labviewNv
32. ons due to defects in materials and workmanship for a period of 90 days from date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period National Instruments does not warrant that the operation of the software shall be uninterrupted or error free A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this document is accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR F
33. r teaches you step by step how to create an application in LabVIEW It also guides you through the Search Examples feature to help you find examples in LabVIEW You will learn to do the following Create a new program in LabVIEW The VI you build generates data analyzes it then writes it to a file Use the Search Examples feature to find and run an example Search for Examples After completing the LabVIEW Tutorial you are ready to run some examples in LabVIEW You can complete this activity in approximately 5 minutes 1 i N National Instruments Corporation In the LabVIEW dialog box click the Search Examples button to open the Search Examples online help which lists LabVIEW examples Either launch LabVIEW or close all open VIs if you are already running LabVIEW to access the LabVIEW dialog box Select Analysis in the Demonstrations category Click Temperature System Demo to open this demonstration VI Click the Run button on the front panel toolbar to see how the VI runs Click the sliders knobs and other controls to see how they affect the data Stop the program by clicking the Acquisition switch to the off position 2 1 Getting Started with LabVIEW Chapter 2 Virtual Instruments Build a Virtual Instrument This activity demonstrates how you can plot analyze and save data in LabVIEW You can complete this activity in approximately 30 minutes Create a User Interface You can crea
34. raries and utilities developed by our Alliance members to help you use LabVIEW In addition the Alliance Solutions directory lists expert LabVIEW consultants who can help you develop custom applications 5 2 www ni com System Requirements The following table describes the required system configurations for running LabVIEW on Windows Macintosh and UNIX platforms Media and System Platform Requirements Important Notes All Platforms Distributed on CD ROM LabVIEW and the LabVIEW Help contain 16 bit color graphics LabVIEW requires a minimum color palette setting of 256 colors 16 bit color is recommended The LabVIEW Help requires a minimum color palette setting of 256 colors with a screen resolution of 1024 x 768 pixels 16 bit color is recommended All Windows Refer to the installation To use the Measurement amp Automation Versions instruction that appear on Explorer you must have Microsoft Internet your screen for information Explorer 5 0 or later installed ap aay The LabVIEW Tutorial requires a sound y y 8 card a video card capable of playing avi LabVIEW runs on any files and a minimum color palette setting of system that supports 256 colors with a screen resolution of Windows 1024 x 768 pixels 16 bit color is recommended Windows NT LabVIEW runs on To take advantage of ActiveX functionality Windows NT 4 0 Service in LabVIEW 6 0 you must have Pack 3 or later Windows NT 4 0 Service Pac
35. rd The Channel Wizard also can be accessed from the DAQ Solution Wizard You can complete this activity in approximately 15 minutes Configuring Analog Input Channels The DAQ Solution Wizard guides you through naming and configuring analog and digital channels using the DAQ Channel Wizard The DAQ Channel Wizard helps you define the physical quantities you are measuring or generating on each DAQ hardware channel It queries for information about the physical quantity being measured the sensor or actuator being used and the associated DAQ hardware You can complete this section in approximately 5 minutes 1 Click the DAQ Solutions button in the LabVIEW dialog box to launch the DAQ Solution Wizard and get started with analog input quickly and easily National Instruments Corporation 3 3 Getting Started with LabVIEW Chapter 3 Measurement Getting Started with LabVIEW 10 Either launch LabVIEW or close all open VIs if you are already running LabVIEW to access the LabVIEW dialog box When the Welcome to the DAQ Solution Wizard dialog box opens click the Go to DAQ Channel Wizard button Windows Select the Data Neighborhood view in Measurement amp Automation Explorer Right click Data Neighborhood and select Create New from the shortcut menu to configure a new channel In the Create New dialog box select Virtual Channel and click the Finish button Macintosh Select New Channel to configure a new channel T
36. ressing lt Ctrl H gt When you place a VI on the block diagram and pass the mouse cursor over it the VI description displays in the Context Help window Click the lock button at the bottom of the Context Help window to lock the current contents of the window l er Access the LabVIEW Help file to search for particular topics by selecting Help Contents and Index You also can right click any built in VI or function on the block diagram and select Help from the shortcut menu National Instruments Corporation 5 1 Getting Started with LabVIEW Chapter 5 Where to Go from Here National Instruments Commitment to You LabVIEW represents a long standing commitment by National Instruments to provide tools that simplify the development of instrumentation data acquisition and control systems When you choose LabVIEW as your development environment you join thousands of scientists and engineers who are taking advantage of the power of graphical programming Customer Education Alliance Program Getting Started with LabVIEW For additional training National Instruments offers interactive CDs videos books and hands on LabVIEW courses to help you master LabVIEW quickly and develop successful applications The Alliance Program is a network of third party developers and consultants who are experts in LabVIEW and other National Instruments products The National Instruments Alliance Solutions directory lists additional lib
37. rols and Functions Palettes 1 6 Data gl 1 6 Where Start iene i a eel A re e ES 1 7 LabVIEW eee 1 7 Chapter 2 Virtual Instruments Search for Examples ete e Hiv aie ase 2 1 Build a Virtual Instrument enne 2 2 Create a User Interface eo RI tere e oie ie e LP eR tants 2 2 Build the Block Diagram titre ree en 2 4 Ware and R n the VL eene e eeu re E S MESE IEEE ares 2 5 Add Timing to the VI eee RI REOR RR PIER 2 8 Add Analysis and File I O to the VI sss 2 9 Chapter 3 Measurement I str ment seo or PUR ERE UE 3 1 Run the Demo Scope VI eet etre erre tcr rero 3 2 Data Acquisition nio dre t raro OU rr p pe pei drerit Er erbe 3 2 Using the DAQ Solution Wizard essere 3 3 Configuring Analog Input Channels eee 3 3 Generating a Solution from the Solutions Gallery 3 5 Adding Analog Input to the VI 3 6 National Instruments Corporation V Getting Started with LabVIEW Contents Chapter 4 Debugging Use Execution Highlighting spritsen neresi nnne 4 1 Sinel Step With Probes sari eO latere e aee vam Rees 4 1 Chapter 5 Where to Go from Here Online Help uote MES ASA Hei ais eren E 5 1 National Instruments Commitment to You esses nnne 5 2 Customer Education
38. s By using LabVIEW to prototype design test and implement your instrument systems you can reduce system development time and increase productivity by a factor of 4 to 10 LabVIEW also gives you the benefits of a large installed user base years of product feedback and powerful add on tools Finally National Instruments technical support and Developer Zone ensure successful development of your solutions How Does LabVIEW Work Getting Started with LabVIEW LabVIEW programs are called virtual instruments or VIs because their appearance and operation imitate physical instruments such as oscilloscopes and multimeters Every VI uses functions that manipulate input from the user interface or other sources and display that information or move it to other files or other computers A VI contains the following three components Front panel Serves as the user interface e Block diagram Contains the graphical source code of the VI that defines its functionality e Icon and connector pane lIdentifies the VI so that you can use the VI in another VI A VI within another VI is called a subVI A subVI corresponds to a subroutine in text based programming languages 1 2 www ni com Chapter 1 Introduction to LabVIEW Front Panel The front panel is the user interface of the VI You build the front panel with controls and indicators which are the interactive input and output terminals of the VI respectively Controls are knobs
39. se to close the Measurement amp Automation Explorer Windows Select Quit to exit the DAQ Channel Wizard Macintosh 3 4 www ni com Chapter 3 Measurement X MAX Temperature 1 File view Help ESi Properties S Test Configuration Fs Temperature 1 My System TU Channel Name Temperature 1 The name of the channel em i rite PJ pescription IC Temp Sensor The Description of the channel GA Temperature 1 L channel Type The Virtual Channel Type A Devices and Interfaces Device Name The name of the device with which t 8 PCI MIO 16XE 10 Device 1 3 Scales Software Generating a Solution from the Solutions Gallery Once you have configured the channel you can generate a solution from the Solutions Gallery You can complete this section in approximately 10 minutes 1 When you return to the Solution Wizard select Use channel names specified in DAQ Channel Wizard and click the Next button 2 Select Solutions Gallery and click the Next button to open the Solutions Gallery 3 Choose a solution to generate for the analog input channel For this example in the Gallery Categories list select Data Logging 4 In the Common Solutions list select Simple Data Logger Click the Next button to continue Select the channel name you configured in the DAQ Channel Wizard as the input channel to use for the s
40. te a graphical user interface on the front panel using controls and indicators on the Controls palette You can complete this section in approximately 5 minutes 1 Create a new VI by selecting New VI in the LabVIEW dialog box Either launch LabVIEW or close all open VIs if you are already running LabVIEW to access the LabVIEW dialog box 2 Create a stop button by selecting Controls Boolean Stop Button on the Controls palette as shown in the following illustration Right click the object and select Visible Items Label from the shortcut menu to show or hide the text label for an object Use the Positioning tool on the Tools palette to rearrange or E resize objects Select Window Show Tools Palette to show the Tools palette Getting Started with LabVIEW 2 2 www ni com b 212 National Instruments Corporation 3 Chapter 2 Virtual Instruments Untitled 1 gt i 13 Font f forfa ERESEI Stop Button Use the Up navigation button on the Controls palette to navigate back to the main Controls palette Create a waveform chart by selecting Controls Graph Waveform Chart This chart plots data one point at a time Use the Labeling tool on the Tools palette to label the waveform chart Random Plot Select Window Show Tools Palette to show the Tools palette Use the Operating tool on the Tools palette to change the scale of the waveform chart Double click 10 0 on the Y axis of th
41. uments Corporation Trademarks LabVIEW National Instruments ni com NI DAQ and are trademarks of National Instruments Corporation Product and company names mentioned herein are trademarks or trade names of their respective companies WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS 1 NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN 2 IN ANY APPLICATION INCLUDING THE ABOVE RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY COMPUTER HARDWARE MALFUNCTIONS COMPUTER OPERATING SYSTEM SOFTWARE FITNESS FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION INSTALLATION ERRORS SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES TRANSIENT FAILURES OF ELECTRONIC SYSTEMS HARDWARE AND OR SOFTWARE UNANTICIPATED USES OR MISUSES OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED SYSTEM FAILURES ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS INCLUDING THE
42. y Version 2 Intel x86 processors with glibc2 also known as 1ibc so 6 Kernel Versione RedHat Linux 5 0 or later includes the LabVIEW runs on most 1 NE glibc2 run time library major Linux distributions such as RedHat Calderra SuSE and Debian National Instruments Corporation A 3 Getting Started with LabVIEW Technical Support Resources Web Support National Instruments Web support is your first stop for help in solving installation configuration and application problems and questions Online problem solving and diagnostic resources include frequently asked questions knowledge bases product specific troubleshooting wizards manuals drivers software updates and more Web support is available through the Technical Support section of www ni com NI Developer Zone The NI Developer Zone at zone ni comis the essential resource for building measurement and automation systems At the NI Developer Zone you can easily access the latest example programs system configurators tutorials technical news as well as a community of developers ready to share their own techniques Customer Education National Instruments provides a number of alternatives to satisfy your training needs from self paced tutorials videos and interactive CDs to instructor led hands on courses at locations around the world Visit the Customer Education section of www ni com for online course schedules syllabi training cent
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