Session T1D AN INTRODUCTION TO LABVIEW EXERCISE FOR AN ELECTRONICS CLASS Melanie L Higa D a h M Taw and Susan M Lord3 Abstract National Instruments LabVIEW has become a popular programming environment for data acquisition in academia and industry Most LabVlEWreference materials require a significant investment oftime At the University of San Diego USD we wanted to provide an introduction to LabVIEW for all electrical engineering majors without adding additional classes or laborutories to the curriculum During a summer research experience two electrical engineering juniors at USD wrote a tutorial on LabVIEW and designed a one hour exercise to introduce students to LabVIEW The exercise allowed students to obtain the amplitudefrequency response ofa simple RC circuit using a function generator and an oscilloscope Students had previously done this experiment manually in their sophomore circuits clnss Thus the concepts ofthe lob were familiar and they couldfocus on the advantages ofhaving LabVlEW automate the data acquisition and analysis Twenty one students in a junior level Electronics course performed the Introduction to LabVIEW exercise in Fall 2001 Index Terms circuits electronics frequency response LabVlEW INTRODUCTION LabVIEW Labratory Virtual Instrument Fngineering Workbench is a graphical programming language which was developed in 1986 by National Instruments l LabVIEW has become a vital tool for engineers and scientists in research throughout academia industry and government labs Although many reference books 2 exist to help one learn to program using LabVIEW most of these require a significant investment of time At the University of San Diego USD we wanted to provide an introduction to LabVlEW for all electrical engineering majors without adding additional classes or laboratories to the curriculum During a summer research experience two electrical engineering juniors at USD wrote a tutorial on LabVIEW and designed a one hour exercise to introduce students to LabVIEW The exercise that was chosen examined the behavior of simple RC filters 3 Students had previously performed this experiment in their sophomore circuits class FIGURE 1 LabVlEW FRONT PANEL OF AMPLITUDE FREQUENCY RESPONSE PROGRAM Melanie L Hi DI D o D v edu Dalia M Tawy University of San Diego Department of Engineering 5998 Alfala Park San Diego CA 921 10 dtawy sandiego edu Susan M Lord University of San Diego Department of Enginccring 5998 Alcala Park San Diego CA 921 10 slord sandieEo edu 0 7803 7444 4 02 17 00 0 2002 IEEE November 6 9 2002 Boston MA 32 ASEEJTEEE Frontiers in Education Conference TID 13 Session T1D In this exercise frequency is incremented on the function generator by one student while another student records the frequency and the corresponding output voltage and input voltage readings from the oscilloscope into an Excel spreadsheet Then the students calculate the magnitude of the voltage gain using equation I Gain A Va Vn 1 When all the gains are calculated an amplitude frequency response gain versus frequency graph is generated in Excel Even after all the work of collecting data students did not always obtain a satisfactory gain versus frequency graph In designing the LabVlEW exercise we decided to eliminate as much human interaction as possible and reduce the time it takes to obtain the graph We hoped this would result in better data and the possibility of having students obtain more data and focus more on data analysis rather than collection We chose to use the available equipment since this exercise would be performed by all students Our department s budget and that of many others does not permit buying specialized equipment for each station to obtain thesc measurements Frequency response is a common measurement in electrical engineering and there are several reports in the literature of student projects resulting in a system that can provide such data 4 5 Note that the lattcr project also provided phase versus frequency data and considerable effort was devoted to that Our project had a smaller scope than either of these and was intended to be used by all electrical engineering majors but only as an introduction to LabVIEW Figure I shows the front panel of the amplitude frequency response program which acts as a user interface between the students and the equipment The front panel includes the collected data points and the amplitude frequency rcsponse graph LABORATORY EXERCISE In order for students to become acquainted with LabVIEW we decided that they would need a brief tutorial Of the LabVIEW reference books considered those by Beyon l and Bishop 6 proved to be the most useful in developing this One of the authors MLH wrote a 5 page Introduction to LabVIEW which summanzed the main features that students would need to know to make some simple modifications to an existing program Students were given this tutorial to read before performing this laboratory exercise Copies of the tutorial as well as the LabVlEW code are a