LabVIEW Quick Start. W. Durfee, University of Minnesota October, 2009

Transcription

1 LabVIEW Quick Start W. Durfee, University of Minnesota October, 2009 LabVIEW is a software product from National Instruments for data acquisition, signal processing, instrument control and industrial automation. It is the most popular application for computer-based data collection and control of an experiment, and widely used by industry. The LabVIEW home page is The objective of this quick start guide is for you to learn a few of the very basic principles of LabVIEW through hands-on activities that do not require data acquisition hardware. You will download and install the 30-day trial version of LabVIEW and device drivers on your computer and go through a LabVIEW exercise created by National Instruments. A second exercise has you writing a custom application to convert temperature readings from Celsius to Fahrenheit. The first exercise will take about 30 minutes and the second about 15 minutes. It will take much longer to download and install the software so plan accordingly. You will be using the full version of LabVIEW but it will only work for 30 days after installation. Getting LabVIEW To obtain LabVIEW, from the home page of the ME2011 course web site, see the LabVIEW Resources page. The following instructions are for a Windows Vista machine. Your configuration may differ in some of the details. Download LabVIEW Download the LabVIEW 30-day trial version software following the instructions on the NI site. Once downloaded, open the downloaded file to unzip. The install dialog opens automatically. Follow all prompts. The install takes about 10 minutes. Towards the end, you may get a dialog asking about installing National Instruments Device Drivers. Click the Later button. If asked to restart your computer, do so. The Download utility may start again, but you can cancel it. Download Device Drivers The device drivers are contained in the National Instruments program NI-DAQmx. This is a *very* large program because it contains the drivers for *all* NI hardware. Warning: It will take a *long* time to download and install the NI-DAQmx software. Download the drivers. After the download is complete, the self-extractor and the installation will proceed semi-automatically, with some assisting clicks from you. Your computer may need to be restarted during the process. Page 1 of 8

2 Running LabVIEW After installation, you will have a NI Measurement & Automation icon on the desktop. Opening takes you to the NI Explorer as shown here In the left pane, open the Software entry and from there open LabVIEW 2009 to start LabVIEW. Or, a simpler way to start LabVIEW, which bypasses the NI Explorer is from the desktop: Start Button > Programs > National Instruments > LabVIEW 2009 > LabVIEW. When you open LabVIEW, this dialog will appear which tells how many days remain on the trial. Page 2 of 8

3 Click the Launch LabVIEW button and the Getting Started window will appear Exercise 1: A First VI You are now ready for the 30 minute exercise, which is to go through the exercise in the Getting Started with LabVIEW Virtual Instruments document that can be obtained from the ME2011 LabVIEW resources page. Congratulations, you now know the basics of LabVIEW. Later, you will learn how to connect LabVIEW to data acquisition hardware to collect measurements from an experiment. Page 3 of 8

4 Exercise 2: A Temperature Conversion VI The purpose of this exercise is for you to learn how to create a new virtual instrument (VI) from scratch, which in this case will be an application to convert degrees Celsius to degrees Fahrenheit. Start LabVIEW and get to the Getting Started window. Under New, click on Blank VI to start a new VI. The Front Panel and Block Diagram windows will open. Activate the Front Panel window. If the Controls palette is not visible, on the Front Panel select View > Controls Palette. The Controls palette looks like this Page 4 of 8

5 On the Controls palette, under Express, click on Num Ctrls to reveal the desired controls. Place two instances of the Num Ctrl on the Front Panel. After placing, right click on the control and select Properties. Change the label of the left control to Degrees C and the right to Degrees F. The Front Panel will look like this Switch to the Block Diagram (Ctrl-E) and bring up the Functions palette (View > Functions Palette). Page 5 of 8

6 In the Functions palette, select Express then Arith & Compar. Place a Formula block on the block diagram. The Configure Formula dialog automatically opens (if not, right-click on the block, then select Properties). Enter the degrees C to degrees F conversion formula where X1 is the input (degrees C) and the result of the formula is the output (degrees F). The formula is X1* and the dialog box looks like Page 6 of 8

7 Now is a good time to save your work. File > Save. Save to the Desktop and give it the name TempConvert. The Block Diagram now looks like R-click on the Degrees F control and select Change to Indicator. Wire the Degrees C control to X1 on the formula box and wire Result on the formula box to the Degrees F indicator, like this Page 7 of 8

8 Switch back to the Front Panel (Ctrl-E). Save your work. Select the Run Continuously button the Abort button. and test out your application. Stop the application with Congratulations, you now know how to build a VI from scratch. If you are in UMN course ME2011 and have the USB-6008 data acquisition unit, proceed to the Connecting the USB-6008 document, which can be found on the LabVIEW resources page of the ME2011 web site. Page 8 of 8