Electronics Laboratory Practices Based on Virtual Instrumentation
Contents
1. November 10 13 1999 San Juan Puerto Rico 29 ASEE IEEE Frontiers in Education Conference 12c6 102. In 90 s decade programmable instrumentation based on GPIB and VXI 2 buses has reached a great spread allowing ATE systems design with multiple computer platforms and several operating systems creating the virtual instrument concept Currently the advance impulse for GPIB performances and new architectures for programmable instruments is sustained from manufactures users and researchers For example National Instruments manufacturer introduced respectively the HS488 specification in 1993 oriented to reach a maximum byte rate of 8 MBps in GPIB and the PXI PCI eXtensions for Instrumentation architecture in 1997 based on Compact PCI 3 4 for modular instruments over electronic cards ATE System Description In their digital communications laboratory the authors have designed a programmable instrumentation system SIP based on IEEE 488 GPIB and VXI VME eXtensions for Instrumentation buses where the GPIB bus connects all programmable instruments to laboratory s PCs by means a 0 7803 5643 8 99 10 00 1999 IEEE LAN 5 The interface between LAN and GPIB bus is made with the Gateway LAN HP IB HP E2050 6 The VXI bus 2 7 8 is configured in a mainframe for instrument modules in size C cards and connected to the LAN through the GPIB bus being its software development tool the environment VEE 4 0 from HP 9 10 11 The figure 1 shows the ATE system configuration SIP PC s for tradeing LAN LAM
3. the interrupt routine and read the data from bus For avoiding the possible loss of data because of GPIB bus higher speed compared with the reading speed of a conventional parallel port the interrupt routine of WATCH_GPIB program stops temporarily bus activity until reading the suitable data C Start gt e 3 Rn f xe b flu e ae aa l TEA Moanting of circuit buname J development toals ie an Sat Sec Y vi peee oa o Dare atta Fam the prograsi Test End Es GFE Bin Moaltar wo A hi Flerchat fer dociguing COEK gt practices in WEE aa Y Pg Conclusions Ee C End a Flowchart fer iaplementing practices Figure 4 Flowcharts for implementing and designing laboratory practices Using the GPIB Bus Monitor the students can visualize the commands and data that is sending through the bus a particular instrument from SIP Figure 1 Implementation of Practices The practices are designed in such a way that students can handle the development environment and visualize the GPIB bus The two first practices are oriented to introduce them the VEE tool and explaining SIP configuration Both are shown in auto learning form and introduce step by step the method of using the VEE environment and the control of instruments for making the practices according the flowchart of figure 4a Following practices allow students developing their own programs using existing tool
4. Gateway has the network server software and adequate firmware for implementing the interface between instruments and LAN The rack and stack GPIB instruments include the firmware with bus drivers Command module slot O of chassis from VXI mainframe 17 22 incorporates the needed drivers for VXI GPIB interface The PC Bus Monitor only takes the signals from GPIB bus lines for displaying them on the screen paragraph 4 Development of Training Program The growing technological development in the programmable instrumentation field has allowed to authors the implementation of applied research projects with these kinds of instruments 1 and applications oriented to teaching electronics In this way one of largely applications of VXI bus has been the automation of measurement and testing over electronic circuits implemented by the students Simultaneously have been designed practices oriented to evaluation and analysis of GPIB bus activity The students have access to SIP through PC s connected to LAN with the VEE programming tool and SICL libraries Figure 2 that respectively allow implementing the measurement and testing application and mastering the instruments Also the students can see the commands and data behavior through GPIB bus by means a PC devoted to this task Figure 1 Bus Monitor Table 1 Features of equipments that conform the SIP mement HP GS22A DC Power GPIB 2 Outputs of BU W al TVED A ZOWA A o Suppir
5. 99 San Juan Puerto Rico 29 ASEE IEEE Frontiers in Education Conference 12c6 9 Conclusions The use of communications networks for implementing laboratory practices based on programmable instrumentation introduces electronic engineering students to designing configuring and developing distributed ATE systems This work introduces a programmable instrumentation system SIP development with GPIB and VXI instruments connected to PC s by means of a LAN The training program is started with the introduction to knowledge of VEE programming tool and follows implementing test and measurements over electronic circuits designed by students Also are added practices for evaluating and analyzing GPIB s bus signals Finally basic knowledge required from students are defined in order to obtain the best progress from practices and are analyzed the obtained results from the point of view of students Also are introduced the future developments that authors are involved for improving both programmable instrumentation practices and ATE system that runs them Acknowledgements This work has been sponsored by R amp D NATIONAL SECRETARY AND CICYT from CENTRAL GOVERNMENT Madrid Spain inside of research project Ref TIC97 0414 References 1 Mari o P amp Dominguez M A Image Processing and Automated Testing in Flexible Manufacturing Systems Proceedings of the 37th SICE Annual Conference IEEE98TH 8377 pp 1121 1126 Chib
6. C a te Piet aera flea tie Tak Talat ak Ta ate tae Tle Take Cale tak Tia gt gt gt gt gt Ma gt Figure 3 Screen of WATCH_GPIB program The GPIB Bus Monitor Figure 1 designed for teaching the IEEE 488 instrumentation bus allows to display in real time and without lost of information the signal lines that conform the GPIB bus Given that a device can only access the bus when it is addressed the GPIB Bus Monitor must not be a bus device since it must read the state continuously and for this reason it must not have any address consequently it does not exist from the controller and the whole bus devices point of view The GPIB Bus Monitor has been implemented by means of a PC under MS DOS Table 1 The GPIB interface cards able to connect a PC to the bus do not allow the access to it in a different time to the card has been addressed by the controller and therefore are not useful for this purpose For this reason is used an I O Card adapted for reading the eight data lines and the eight control lines of GPIB bus The Bus Monitor runs the WATCH_GPIB program that allows gathering and displaying in real time the available data on 0 7803 5643 8 99 10 00 1999 IEEE Session 12c6 GPIB bus or displaying stored data in a file Figure 3 This program loads in the computer memory an interrupt control routine and associates it to parallel port IRQ7 The line SRQ Service Request from GPIB bus 5 8 is used to fire
7. SOW ie A OY TAA HF 478A Multameter GPE La Wine ii Vinac 3 Ag Aum 250 HF E140LA High VRIGME C Sire 13 slots conmector PLZ Power Malai ane HP EIGA Vel GP TB BS 242 slot 2MB Ram Memeee based orm md Fiotuje Controller HF Fidei YE I channels Jess 250 MHz Qeedhecope i x HF EFidioa Wx Zo 4 Wire fh Yoa Time EMS Dom HZ to Mutimeter IMH HF E4206 Universal WR 2a HHZ tie F ialt teut h Counter HF F1d45 4 Function WI I3 bt recolmtion 40 Meats 156 Ke wanefonn Gierak Femer Memory HF EHC Reg YAI l bitregister based mterface FI comector Based Rreadhoand HP Fides 16x16 Wil l xl6 teo wire 1 AL DY signal switching Rey Matrix CHELAN GPR Instrumentation vie LAN SICLWISA yee OD 466 PC RAM L MB LO pork HP ESSA Gateway GPIB Bus Honi Paralel 0 7803 5643 8 99 10 00 1999 IEEE Session 12c6 The VEE Visual Engineering Environment tool is a graphic programming language particularly designed for driving programmable instruments When the instruments are connected to GPIB bus the student send commands and data following the training program by means of the LAN s PC That PC will receive the replay and will perform data analyzing displaying graphic results or storing data for later processing er Cleri HP FHN GFE hormat Vi Mamia CFIH Bay Mienia e Tee LAN lnierine CFE Interfare LAM Figure 2 Software firmware architecture of SIP For easing th
8. Session 12c6 Electronics Laboratory Practices Based on Virtual Instrumentation P Marino J Nogueira and H Hernandez E T S Ingenieros Industriales Departamento de Tecnologia Electronica Universidad de Vigo Apdo Oficial 36200 Vigo Spain Doctor on Telecommunications Engineering pmarino uvigo es Telecommunications Engineer nogueira uvigo es Electronic Engineer hhdez dte uvigo es hhdez mixteco utm mx Abstract The authors present an ATE system designed for teaching practices about programmable electronic instrumentation by means of GPIB and VXI instruments connected to a local area network LAN The aim of this system intended for students of electronic engineering is the introduction of more relevant technologies involved in hardware instrumentation for ATE applications besides the handling of their software environments for developing programs Introduction Teaching electronic instrumentation for engineering students has a great impact about their basic training on technologies oriented to design systems for process control product verification services operation quality analysis etc over all economic sectors The growing advance in microelectronics given its continuos reduction in cost and increasing processing power and lower size with higher performance of software packages have boosted the presence of powerful systems for automated test equipment ATE based on programmable instrumentation 1
9. VHPTE Chaneuay GAE Miani ii HP ENDLA WAL Hamru Figure 1 ATE system configuration SIP of programmable instrumentation laboratory The Gateway connects the lab s PC network to the GPIB bus following client server model 2 where each PC performs as a client and the Gateway as server 6 12 13 In this way applications running in clients can communicate with instruments based in GPIB bus in a transparent mode through LAN This allows several students access to programmable instruments and sharing in this way the SIP resources The Gateway can be installed in any place of network depending on instruments location and GPIB s cable length Instrument identification is reduced to a simple logical address Table 1 summarizes the features of equipments that conform the SIP two GPIB rack and stack instruments DC power supply 14 and multimeter 15 a VXI mainframe 3 7 16 with eight connected instruments 14 15 and November 10 13 1999 San Juan Puerto Rico 29 ASEE IEEE Frontiers in Education Conference 12c6 6 17 to 25 the Gateway and a PC with WATCH_GPIB software developed by the authors that performs the bus monitor function paragraph 4 Figure 2 depicts the software firmware architecture of SIP where each client computer under operating system Windows 95 NT and with VEE tool manages the intended programs to control instruments SICL Standard Instrument Control Library and LAN access TCP IP The
10. a Japan July 29 31 1998 2 HEWLETT PACKARD Test System and VXI Products Catalog Hewlett Packard Company 1997 3 NATIONAL INSTRUMENTS Instrumentation Catalogue Measurement and Automation National Instruments 1998 4 NATIONAL INSTRUMENTS PXI Specification Rev 1 0 National Instruments 1997 5 Marino P Enterprise wide communications standards networks and services RA MA Madrid Spain 1995 6 HEWLETT PACKARD HP E2050 LAN HP IB Gateway Hewlett Packard Company 1996 7 Black J editor The system engineer s handbook Academic Press 1992 8 Mandado E Mari o P amp Lago A Electronic Instrumentation Marcombo Barcelona Spain 1995 9 HEWLETT PACKARD Building an Operator Interface with HP VEE Hewlett Packard Company 1995 0 7803 5643 8 99 10 00 1999 IEEE Session 12c6 10 HEWLETT PACKARD Exploring HP VEE Hewlett Packard Company 1995 11 HEWLETT PACKARD How to Use HP VEE Hewlett Packard Company 1995 12 HEWLETT PACKARD Installing the HP IB Interface Hewlett Packard Company 1994 13 HEWLETT PACKARD HP 82335 82340 amp 82341HP IB Interface Hewlett Packard Company 1996 14 HEWLETT PACKARD Operating Manual System DC Power supplies HP models 6621A 6622A 6623A 6624A and5527A Hewlett Packard Company 1993 15 HEWLETT PACKARD HP 3478A Multimeter Operator s Manual Hewlett Packard Company 1988 16 TEKTRONIX VX bus System Specifications Re
11. aying an instrumentation bus control signals besides implementing electronic circuits testing Generalization of SIP from general purpose practices to more specific ones such as power electronics engines control network analysis etc Future developments about new advanced practices and the SIP configuration are Using a VXI register based breadboard module 25 for designing new compatible instruments 1 e A D and D A converters sensors and effectors conditioners etc Implementing automatic evaluation of student throughput during their training time Including the new PXI bus for instrumentation paragraph 1 Migrating compatible instrument controllers to VXIplug amp play standard currently in growing acceptance and using VISA Virtual Instrument Software programmable Architecture libraries 2 3 30 Remote training through Internet over the developed SIP Experiments with Mixteca Technological University Oaxaca Mexico are started Orc Comprebando el funcionamiento dela Placa No E Z M Dea War Mie Mey beste el a E a M PS me ow fears Map a wen ee ee TS eae ow fea pe Ares ore ow pe eee a we we FR ee cae aoe RT hs TS ove we te pS TSF Sona farsa pa sa we pea pee Pg m fred freq a mA wi m oar Pee re ee e e oe oe es Foe wa e Rego 7 wi vo peg a mogl orl pa a ma a wt fea feel Mt Figure 6 Interface of automated testing program for electronic boards November 10 13 19
12. e control of programmable instruments in the development of ATE systems usually are selected high level programming languages such as C C Visual Basic and so on In this application is used the VEE programming language that allows simplifying the task of interface design data acquisition processing and displaying of results Table 2 Comparison between control types of instruments YEE Acces te nuri nents Advantages Supporii ig Ohjects Interfaces Dire Pith Dier cominrenication withthe High ommani speed Allows to GPIB Serial mR Cire avin iera VXI aad LAN High speed of enmena GPIB and Controllers are remeni for malliple WX application parane Fier of ising Higher chnan seed with compan driver Phage DO Requires a controller af the inetruments Ghat fits into Y wP Aar law sinnlard Panel Driver Eppie a comivall T aril Driver There are three control types of instruments in VEE 26 27 28 Direct I O Drivers and PC Plug in I O which main features are shown in table 2 Laboratory practices have been designed in order to easily introduce the students about the three control types and acquaint them with application needs and available tools This way is justified since this application does not use the PC Plug in I O alternative given it needs a particular card VXIplug amp play for implementing the interface contrary to the cases of Direct I O and Drivers Although Direct I O requires the k
13. nowledge of SICL s instructions nevertheless it provides high communication speed and does not need the instrument driver the control type most frequently used in advanced practices Otherwise VEE gives a new object called Multidevice Direct I O that gets the control of several instruments through the edition of only one object The controllers can be the control panel of the instrument Panel November 10 13 1999 San Juan Puerto Rico 29 ASEE IEEE Frontiers in Education Conference 12c6 7 Driver or a part of controller Component Driver In this application the use of instrument control tools is oriented to teaching and handling control panels is very important given that students learn to operate the whole choices of each instrument easily When there is no enough knowledge about SICL s instructions or choices of an instrument the Component Driver is the best solution because it provides higher speed and only sends and receives the needed data for implementing a particular task Also this object has a list of instructions and information for supporting the learning about choices of each instrument GPIB Bus Monitor The programmable instrumentation GPIB bus is a parallel connection bus in which all devices share the line signals 3 5 29 and requires the existence of some equipment for mastering those signals Ss MS DOS WATCH cae Piel ES le Rl iit AT gt PSS BN Vw E E BN AA NN A A ge SEO CA
14. s and at any time they can access directly to the SIP for connecting their electronic circuits under test For example the practice three is oriented to design a VEE program using the needed instruments for implementing Bode s diagrams module and phase of a RC circuit frequency response Also shown to the students are the choices used to identify and compare the three control types of instruments Table 2 and the way VEE objects are November 10 13 1999 San Juan Puerto Rico 29 ASEE IEEE Frontiers in Education Conference 12c6 8 connected following respectively the flow of execution and sequence Emphasized is the control of instruments Figure 4b with the aim that students can identify correctly the working tools The results of this practice are depicted in figure 5 This interaction with the development environment allows students a better use of the graphic language and the handling of the powerful mathematical functions provided by VEE Figure 5 Instance of a practice in VEE Other example is practice nine devoted to the automated testing of electronic boards in which the students have a board designed for teaching electronic devices with the aim of designing a graphical interface able to display the results obtained from testing the whole components of board Basically the control of instruments is made given input signals to the board and supported by HP E1465A relay matrix switch module 20 implementing the righ
15. t connection of instruments for making measurements of resistence AC DC voltages and currents period frequency and polarity test of diodes The results are shown in figure 6 In each practice is the optional use of the GPIB Bus Monitor which shows continuously the bus information sharing this task with the bus monitoring function provided by VEE provides an useful tool when SICL instructions are applied Background Requirements The set of computer assisted practices designed for teaching programmable instruments to students requires from them the following previous background Circuits theory Basic electronic foundations and electronic components Experience using manual electronic instrumentation Oscilloscope multimeter function generator etc Communication protocols for understanding the SIP configuration which have been trained 0 7803 5643 8 99 10 00 1999 IEEE Session 12c6 Performances of HP VEE working environment Results and Future Developments From the point of view of students the results are Accessing to high cost and modern programmable instrumentation equipment Training in the use of programmable instrumentation currently unavoidable in a growing number of enterprises Knowledge acquisition about a _ largely used instrumentation bus Use of instrumentation buses like general communication resources if it were needed 1 e file transfers between computers Displ
16. vision 1 4 Tektronix Inc May 1992 17 HEWLETT PACKARD High Power Mainframe HP E1401A User s Service Manual Hewlett Packard Company 1992 18 HEWLETT PACKARD HP E 410A 6 Digit Multimeter User s Manual Hewlett Packard Company 1992 19 HEWLETT PACKARD HP E1445A Arbitrary Function Generator Hewlett Packard Company 1992 20 HEWLETT PACKARD 16x16 4x64 and 8x32 Relay Matrix Switch Modules HP E1465A E1466A E1467A User s 21 HEWLETT PACKARD C Size VXIbus Systems Configuration Guide Hewlett Packard Company 1994 22 HEWLETT PACKARD Command Module HP E1406A User s Manual Hewlett Packard Company 1994 23 HEWLETT PACKARD Universal Counter HP E1420B User s Manual Hewlett Packard Company 1994 24 HEWLETT PACKARD Digitizing Oscilloscope HP E1428A User s Manual Hewlett Packard Company 1994 25 HEWLETT PACKARD HP E1490C C Size VXIbus Register Based Breadboard Module User s Manual Hewlett Packard Company 1996 26 HEWLETT PACKARD HP I O Libraries Hewlett Packard Company 1996 27 HEWLETT PACKARD Controlling Instruments with HP VEE Hewlett Packard Company 1998 28 HEWLETT PACKARD Getting Started with HP VEE Hewlett Packard Company 1998 29 Caristy J IEEE 488 General Purpose Instrumentaci n Bus Manual Academic Press 1989 30 Helsel R Visual programming with HP VEE Hewlett Packard Professional Books third edition 1998 manual Hewlett Packard Company 1993
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