1 March 2011                              VISI                                 IR                              INST LATIO ...
Summary   In December 2010, the Electrical and Computer Engineering Department of Spanish University forDistance Education...
Table of Contents1.       INTRODUCTION ......................................................................................
Glossary API         Application Programming Interface DPST        Double pole, single throw GND         Ground GPIB      ...
Figure IndexFigure 1. Common traditional instruments in an undergraduate ....................................................
Table IndexTable 1. The role of each component of the NI PXI-platform……………………………………………………………..…....8Table 2. Board label a...
1. INTRODUCTION   The Signal Processing Department (ASB) at Bleking Institute of Technology (BTH) in Sweden togetherwith N...
2. HARD          DWARE DESCRIP                      PTION   The common traditiona instrumen in an u   T            n      ...
2.1.       PXI                  I-Platform                           m   The   T PXI plat tform consis of instrum         ...
2.2.     Rel Switch               lay    hing Matri                               ix    It is a stack o PCI/1041 sized boa...
Figure 3. Component Bo                                                              oard   According to the data s   A    ...
In relay swit    n           tching matri each boa has a ce                           ix,         ard       ertain number ...
Fig  gure 6. Internal connection of instruments with the nodes of the matrix                 l             f              ...
The   T complex of the matrix depend on the nu               xity     m           ds          umber of nodes it have e.g. ...
2.2.1. Com             mponent Lis                       st   The   T compone list descr                  ent             ...
Figure 10 Components installed in the component b                                          0.                          e  ...
 Single pole relays on componen board. Fo example, figure 12 e                             n        nt          or       ...
Figure 14 sho how a si   F           ows      imple compo                                  onent list cou look like       ...
3. SOFT          TWARE D                DESCRIP                      PTION AN OPER                             ND   RATION...
3.1.    We Interfac             eb       ce   It is the webp    t           page of VISIR through w   which user c access ...
Av               vailable mod                          dules              Selected modules                                ...
When the client clicks on the com   W                                   mponents but   tton as show in figur 20, a pul    ...
Web    W services prescribe XML based m                           X           messages co                                 ...
3.4.    Equ              uipment S                      Server   It is a stand-    t             -alone equip             ...
Tab 3. The VISI oscilloscope capabilities                                         ble         IR           e              ...
Figure 24. Overall operation process of VISIR   u             l             o                    [25]
4. INSTA           ALLATIO                 ON   Before startin with the installation an overvi   B              ng        ...
Figure 26 Connection o the DMM an the oscillosc                6.           of         nd            copeFigu 27. Connec  ...
4.1.      Lab                bVIEW   LabVIEW is the platform with which the equipm server s   L                     m     ...
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
VISIR INSTALLATION & START-UP GUIDE V.1
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VISIR INSTALLATION & START-UP GUIDE V.1

  1. 1. 1 March 2011 VISI IR INST LATIO & STA TALL ON ART-U UP GUIIDE V V.1 Electrical a Compute Engineering Department and er g t Spanish Un niversity for D Distance Educ cation-UNED Authors: Mohamed T Tawfik Sergio Mar rtín Charo Gil Pablo Losaada Alberto Pessquera Elio Sancristobal Gabriel Díaaz Juan Peire Manuel Castro This w work has been sponsored by the Span nish Science and Innovation Ministry through the project eTIN22008-06083-C C01/TSI “s-Labs – Open s services integ gration for d distributed, r reusable and secure remote andvirtu laboratories” ual
  2. 2. Summary In December 2010, the Electrical and Computer Engineering Department of Spanish University forDistance Education (UNED) [1] installed a Virtual Instrument Systems in Reality (VISIR) [2]. VISIR is aremote laboratory for undergraduate electric and electronic circuits practice. It allows a student towire a real circuit remotely and get results from real instruments on their PC screen. The purpose ofUNED is to apply it, the second semester of this academic year 2010-2011, on the practice of theundergraduate engineering grades. On the other hand, to work on its development and integrationwith other outstanding learning technologies and research areas in which the department is currentlyresearching to improve and enrich distance education. For instance, learning management system(LMS), fingerprints, mobiles, remote laboratories, web services, etc. UNED aims to be an activemember in the VISIR community by sharing its lab resources and experiments with the rest of thecommunity to enhance the experimentation skills in the electric and electronic engineering fields.Furthermore, it aims to bring out satisfactory results with respect to the practice as well as theresearch areas directed to the enhancement of the distance education quality level. This work reflects the acquired experience during the set up and the installation process of VISIRat UNED. The guide contains all the stages of the installation and the necessary configurationsrequired for the VISIR start-up, correct usage and administration. This work aims to be a reference forany university interested in setting up a VISIR and to be a one more contribution from UNED to itscommunity.
  3. 3. Table of Contents1. INTRODUCTION ..................................................................................................................................... 62. HARDWARE DESCRIPTION ................................................................................................................. 7 2.1. PXI-Platform ........................................................................................................................................................................................ 8 2.2. Relay Switching Matrix .................................................................................................................................................................. 9 2.2.1. Component List ........................................................................................................................ 14 2.2.2. Max lists ................................................................................................................................... 173. SOFTWARE DESCRIPTION AND OPERATION CYCLE ................................................................. 18 3.1. Web Interface .................................................................................................................................................................................. 19 3.2. Experiment Client .......................................................................................................................................................................... 19 3.3. Measurement Server .................................................................................................................................................................... 22 3.4. Equipment Server .......................................................................................................................................................................... 234. INSTALLATION .................................................................................................................................... 26 4.1. LabVIEW ............................................................................................................................................................................................ 28 4.2. NI Device Drivers ........................................................................................................................................................................... 28 4.3. Relay Switching Matrix Driver ................................................................................................................................................. 29 4.4. Component List ............................................................................................................................................................................... 29 4.5. Equipment Server Software ...................................................................................................................................................... 30 4.6. Measurement Server .................................................................................................................................................................... 31 4.7. Web Server ....................................................................................................................................................................................... 33 4.7.1. Text_WIKI Package ................................................................................................................. 33 4.7.2. Smarty ....................................................................................................................................... 34 4.8. Web Interface .................................................................................................................................................................................. 34 4.8.1. Database.................................................................................................................................... 35 4.8.2. HTTPS ...................................................................................................................................... 35 4.8.3. Config.php ................................................................................................................................ 38 4.9. Experiment Client .......................................................................................................................................................................... 40 4.9.1. Config.xml ................................................................................................................................ 40 4.9.2. Library.xml ............................................................................................................................... 40 4.10. Getting Started ................................................................................................................................................................................ 415. CONCLUSION AND FUTURE WORK ................................................................................................ 42REFERENCES ............................................................................................................................................... 43
  4. 4. Glossary API Application Programming Interface DPST Double pole, single throw GND Ground GPIB General Purpose Interface Bus HTML Hypertext Markup Language I2C Inter-Integrated Circuit IC socket Integrated circuit socket IEEE Institute of Electrical and Electronics Engineers IP Internet Protocol IVI Interchangeable Virtual Instruments LabVIEW Laboratory Virtual Instrumentation Engineering Workbench LMS Learning management system LXI LAN Extensions for Instrumentation NI National Instruments PXI PCI Extensions for Instrumentation SOAP Simple Object Access Protocol SSL Secure Socket Layer TCP Transmission Control Protocol TLS Transport Layer Security USB Universal Serial Bus VISA Virtual Instrument Software Architecture VISIR Virtual Instrument Systems In Reality [3]
  5. 5. Figure IndexFigure 1. Common traditional instruments in an undergraduate ............................................................... 7Figure 2. Relay switching matrix ................................................................................................................. 9Figure 3. Component Board ...................................................................................................................... 10Figure 4. Two leads components connected to DPST relays .................................................................... 10Figure 5. Internal connection of a resistance connected to relay one and to the nodes (B, C) ................ 11Figure 6. Internal connection of instruments with the nodes of the matrix ............................................... 12Figure 7. A graph with 5 nodes and 10 branches ...................................................................................... 13Figure 8. A circuit of 5 nodes and 3 components ...................................................................................... 13Figure 9. Numbering single and dual pole relays on the component board ............................................. 14Figure 10. Components installed in the component board ........................................................................ 15Figure 11. Internal connection of the 6V power source using shortcut wires........................................... 15Figure 12. Internal connection of the 6V power source using single pole relays ..................................... 16Figure 13. Operational amplifier connection ............................................................................................ 16Figure 14. Component list ......................................................................................................................... 17Figure 15. A max list for an operational amplifier circuit ........................................................................ 17Figure 16. An overview about how VISIR works ....................................................................................... 18Figure 17. VISIR web interface ................................................................................................................. 19Figure 18. Client selects available modules .............................................................................................. 20Figure 19. Virtual workbench of VISIR ..................................................................................................... 20Figure 20. Pull-down component list menu ............................................................................................... 21Figure 21. Measurement server running ................................................................................................... 22Figure 22. Equipment server software running ......................................................................................... 23Figure 23. The role of IVI in the frontal panel and the platform selection ............................................... 24Figure 24. Overall operation process of VISIR ......................................................................................... 25Figure 25. VISIR connected at UNED ....................................................................................................... 26Figure 26. Connection of the DMM and the oscilloscope ......................................................................... 27Figure 27. Connection of the DC power supply and the function generator ............................................ 27Figure 28. Instruments defined in the Measurement & Automation Explorer .......................................... 28Figure 29. Relay switching matrix defined in the Measurement & Automation Explorer ........................ 29Figure 30. EquipmentServer.ini file .......................................................................................................... 30Figure 31. Create wiki page ...................................................................................................................... 41 [4]
  6. 6. Table IndexTable 1. The role of each component of the NI PXI-platform……………………………………………………………..…....8Table 2. Board label and I2C address scheme……………………………….…….…………………………………………………13Table 3. The VISIR oscilloscope capabilities.………………………..………………………………………….……………………24 [5]
  7. 7. 1. INTRODUCTION The Signal Processing Department (ASB) at Bleking Institute of Technology (BTH) in Sweden togetherwith National Instruments in USA (as a supplier of instruments) and Axiom EduTECH in Sweden (as asupplier of education, technical software, and engineering services for noise and vibration analysis) havelaunched the Virtual Instrument Systems in Reality (VISIR) Project in the end of 2006. It is an open sourceremote laboratory project, financially supported by BTH and the Swedish Governmental Agency forInnovation Systems (VINNOVA). In December 2010, the Electric and Computer Engineering Department of UNED installed a VISIR withthe aid and guidance of the project founder Ingvar Gustavsson, together with the two engineers, JohanZackrisson and Kristian Nilsson, from Bleking Institute of Technology (BTH). This guide is an installationreference from the Department. It includes the gained experience during the installation. The guide consistsof four main chapters. The first chapter (Hardware Description) describes the VISIR hardware componentstypes, models and their suitable connection. The second chapter (Software Description and OperationCycle) explains the VISIR operation cycle and the software role of each part during the operation and itssource building. The third chapter (Installation) shows the VISIR installation step by step process at UNEDand all the configurations needed to get it to run. The Fourth and the last chapter (Conclusion and Futureworks) discusses the main parts on which a future work could be realized , on the one hand, for the VISIRdevelopment and integration, and on the other hand to Develop the available remote lab technology andenhance distance education. Most of the compiled information in this guide is retrieved from documents released by the projectfounders through the project webpages [2] [3], all these documents are freely accessible. This guideprovides complementary information to that is found in the project web pages. Accordingly, beforeinstalling a VISIR, the resources of the project web pages should be considered first. [6]
  8. 8. 2. HARD DWARE DESCRIP PTION The common traditiona instrumen in an u T n al nts undergraduat engineeri te ing laborato for elec ory ctric andelect tronic circui Figure 1, are: a po its, ower supply a function generator, a digital m y, n , multi-meter (DMM);brea adboard and an oscillosco ope. Figure 1. Common traditional instrument in an underg ts graduate engineerin laboratory f electric and electronic cir ng for d rcuits In VISIR, the instrume are repla n ese ents aced with an equipment platform, w n which is suite for remot control ed te 1such as PXI (PC eXtension for Instrum h CI ns mentation) [4], LXI (LA eXtensio for Instru AN ons umentation) 2 [5] and 3IEEEE-488or GPI (General Purpose Int IB terface Bus) [6]. The current VISIR is based on PXI. In ad R o ddition, arelay switching matrix is connected to the PXI eq y quipment plaatform. The matrix con nnects the diigital pxiinstr rument cards to the comp s ponents inst talled inside the matrix. By this way it possible to design an wire a y, ndreal electronic c circuit remot tely thanks t this matri In this part, all the V to ix. VISIR hardw ware compon nents aregoin to be desc ng cribed, illustr rating the funnction of eac of them. ch 1. 1 PXI (PCI eXtensions for In nstrumentation) is a rugged PC- -based platform for measureme and automati systems. Wi PXI, you ent ion ith can select t modules (ins the struments) from a large number of vendors and easily integrat them into a si r d te ingle PXI system PXI uses m. PCI-based t technology and an industry stan ndard governed b the PXI Syst by tems Alliance (P PXISA) to ensur standards com re mpliance and system interroperability. 2. 2 LXI is the power of Ethern and the Web applied to Te & Measurem net est ment offering you new possibilit in test syste u ties ems – local, remote, disttributed, time-aw ware. LXI is the current and fut e ture standard for Test & Measur r rement. Its seen the fastest ram n mp-up of any communica ations standard in the history of t test industry and products fro leading test a measuremen companies. n the om and nt 3. 3 GPIB or IEEE-488 is a sho ort-range digital communications bus specificatio It was create for use with automated test e s on. ed a equipment in the late 1960s, and is still in use for that pur n rpose. It was cre eated as HP-IB (HHewlett-Packard Interface Bus). d . [7]
  9. 9. 2.1. PXI I-Platform m The T PXI plat tform consis of instrum sts ment module cards, a co e ontroller car and a cha rd assis in whic all the ch 1card are suited All the pl ds d. latform com mponents are manufactur by National Instrum e red ments (NI) [7]. Forever componen there are a various m ry nt, models depen nding on its technical characteristic Table 1 i cs. illustratesthe r of each component a its available model a UNED role and at Table 1. Th role of each component of the NI PXI-pla he f atform NI PXI-Ch hassis NI N PXI-Mod dules NI-P Control PXI ller Fun nction: It is the backbone of the PXI s e Or NI PXI-Instruments, The modules card ds It is an e embedded PC, which is em in which all instrument syste that substitut the instrum te ments. They ar re plugged int the NI PXI-Chassis. It to cards (NI PXI-mod s dules) and NI plugged into t NI PXI-Cha the assis. All of thes se comes with standard featur such as h res PXI-controller are pl lugged into. cards can be a added and remov depending o ved on an integrate CPU, hard dr ed rive, RAM, the demands. Ethernet, video, keyboa ard/mouse, serial, USB Microsoft win B, ndows etc. All these ddevice drivers a already are installed. Hence, it elim H minates the need for an external PC. H n However, it could be repplaced with a PC C. • NI PXI-Chassis (N PXI-1031). I NI • NI PXI-DC Power Supply ( PXI-4110). C (NI • NI-PXI Controller (NI PX C XI-8105). Model M • NI PXI-Dig gital Multi-meter (NI PXI -4072) r ). inst talled at UNNED: • NI PXI-Fun nction Generator (NI PXI-5412). r . • NI PXI-Osc cilloscope (NI PX XI-5114). 1. 1 National Innstruments is a l leader company for production of automated t y test equipment a virtual instr and rumentation soft tware. Their software prooducts include L LabVIEW, LabW Windows/CVI, T TestStand, etc. T Their hardware p products include VXI, VMEbus, PXI, GPIB, I²C, and oth industrial aut her tomation standar rds. [8]
  10. 10. 2.2. Rel Switch lay hing Matri ix It is a stack o PCI/1041 sized boards [8] which act as a circ t of s cuit-wiring ro obot. It is m manufactured in BTH. dIt is designed for low freque r ency analog e electric and electronic ci ircuit experi iments and cconsists of in nstrumentand component boards. Eac instrumen board (DM Oscillo ch nt MM, oscope, Powe source an function g er nd generatorBoar correspo rd) onds to its NI PXI-Devi in the N PXI-Chas and con N ice NI ssis nnected to it using eithe coaxial ercable or cords, Figure 2. es Figure 2. Re switching matrix elay Relay switch R hing matrix can hold up to 16 com p mponent boards. Each component board comp prises 10sock for comp kets ponents with two leads ( h (Each socket is connecte to a doubl t ed le-pole singl le-throw rela DPST) ayand two 20-pin IC sockets for complex circuit conn f nections. Th relay sw hus, witching matr can cont rix tain up to16×1 relays as maximum. Two leads component occupy on relay wh more leads compon 10 s . ts ne hile nents e.g.amplifier, occup more relay Figure 3. Putting the switching m py ys, . matrix into a closed case is not recom e mmendedbecaause it should be easy to swap comp d ponents and r rewire brancches. Howev it is very important t protect ver, y tothe s switching ma atrix from no on-qualified persons. d 1. 1 PC/104 is a common international embedde computer stan ed ndard controlled by the PC/104 C Consortium. [9]
  11. 11. Figure 3. Component Bo oard According to the data s A o sheet, the m maximum car current of the relay is 2 A an the minim rry y nd mum life 8expe ectancy is 3 3×10 operat tions (appro oximately tw operation per secon continuously for fiv years). wo ns nd veFigu 4 shows t leads co ure two omponents co onnected to DPST relays inside the m matrix. Figure 4. T leads comp Two ponents conne ected to DPST r relays [10]
  12. 12. In relay swit n tching matri each boa has a ce ix, ard ertain number of relays controlling the interco s g onnectionbetw ween the boa compone and the b ard ents board. Howeever, there a common nodes propa are agating with all the hinboar to conne them tog rds ect gether, creati a node b ing bus. These nnodes are diivided into two groups, the first ,conttains the nod A-I and 0 (GND). While the s des d second conta ains the nod X1-X6 and COM as seen in des a sfigur 3. re Figure 5 expl F lains the inte ernal connec ction of a commponent in the compon nent breadboa The com ard. mponentscan be connecte only to t nodes of the first gr ed the f roup depend ding on the components distributio on the oncommponent boar Figure 6 shows the internal co rd. onnection of the instrum f ments with the nodes in t nside thematr The grou terminal of the func rix. und ls ction genera and the o ator oscilloscope are hardwir to node 0 (GND). e redThe function gen nerator outp can be co put onnected to nnode A only While the oscilloscope channels a well as y. e asthe D DMM chann are dyna nels amically con nnected to an node depe ny ending on th user circui design and they are he it dnot llisted in the component list design. T Power s The source conne ectors (0, CO +6V, +20V, -20V, A OM, AUX) areconnnected intern nally to the node 0 (GN and th nodes of the second group (CO GND) he OM, X1, X2, X3, X4)respe ectively, the depending on the com en g mponent list design (see componen list), they are connect to the t e nt tedfirst group (by a shortcut wi as seen in figure 3 or by two rela switches i series) as the second g ire n r ay in group arenot ssupported in the current software ver n rsion. Figure 5. Int ternal connecti of a resista ion ance connected to relay one a to the node (B, C) d and es [11]
  13. 13. Fig gure 6. Internal connection of instruments with the nodes of the matrix l f [12]
  14. 14. The T complex of the matrix depend on the nu xity m ds umber of nodes it have e.g. from a matrix with N nodeswe c obtain N (N-1)/2 br can N. ranches. How wever, the c current matri which hav 10 nodes (A-I, 0) is s ix ve s sufficientfor undergraduat Engineeri practice. Figure 7 sho the num u te ing ows mber of brancches (10) co ould be obtai ined froma5n node circuit. Figur 7. A graph w 5 nodes an 10 branches re with nd s For F instance, if we conne a resistan (R1) to th nodes (A, B), a resista ect nce he ance (R2) to the nodes (B C) and B,a res sistance (R3) to the node (D, E) as s ) es shown in fig gure 8, we wo ould have to consider so facts suc as: o ome ch • The DDMM chann nels are dynnamic but th nodes ar not, so w can meas he re we sure R1, R2, R3 and , R1+R To measu R2+R3 ( R2. ure (nodes B, E) we have to make a sho ), o ortcut betwe the node (C, D). een es The shhortcut is a single wire t connects two nodes and occupie one relay as seen in th relay 3 s that s es he of the matrix of figure 3. If th user conn e fi he nects R2 and R3 in serie the intern shortcut r d es, nal relay will be connnected autoomatically to combine th two nodes the user do o he s, oesn’t have t draw it. to • The fu function gene erator is con nnected only to the node (A, 0), so to connect it to any oth node, y es o her we shhould have a shortcut bet tween the no A and the other node ode e. Figur 8. A circuit o 5 nodes and 3 components re of d s In the matrix, a matrix Controller (PI n C IC18F4550) hosted on t source board commu ) the unicates with a board hconttroller (PIC1 16F767) on eeach board v a bus [8], so that, eac board has a label, whi correspo via , ch ich onds to anaddrress, which w be need later for writing the component list file. Ta will ded r e t able 2 shows each board label at s dUNE with its e ED equivalent I2C address. Tab 2. Board lab and I2C add ble bel ddress scheme Bo oard Type Board Labe el I2C Add dress Co omponent board 1 1 COMP 1 Co omponent board 2 2 COMP 2 Etc. Os scilloscope b board 16 OSC 16 DM board MM 17 DMM 17 7 Etc. So ource board 24 SRC 24 [13]
  15. 15. 2.2.1. Com mponent Lis st The T compone list descr ent omponents a instrume 1 in the m ribes all the installed co and ents matrix to ma them akeknow to the so wn oftware. The is only o compone list per s ere one ent switching m matrix. Next, some guideelines aregiven to list instr ruments and component in the com d ts mponent list f file.  Befor listing a co re omponent w have to co we onsider a ver important remark. The are four dual pole ry ere relays in the comp s ponent board that can be replaced b eight sing pole relay as shown in figure d e by gle ys 9. The 10 dual pole relays a numbered 1, 2,3,5,7, are d ,8,9,10,11 and 13 respe ectively. Wh if we hile replac four of the with 8 si ce em ingle pole relays, they w be numbe will ered (1-14) respectively. r . Figu 9. Number ure ring single and dual pole rela on the comp d ays ponent board  The t leads components (R C, SHORT two R, TCUT, L, etc are listed as the follow c.) wing: <Com mponent typ pe>_<board label>_<re d elay numbe er> <Node e1>< Node2 <etc.> 2> <Value> < For instance, the components installed in the compo n onent board of figure 10 will be described as 0 ollowing: the fo - R_2_1 I IH 10K : represents a resistor of 10K ohm installed on the relay 1 and s ms connected to the nodes (I, H) in th board 2. s he - SHORTCU UT_2_3 HG represents a shortcut installed on the relay 3 and connect to the G: n ted nodes (H, G) in the bo oard 2. - C_2_4 AB A 10n: represents a capacitor of 10n far installed on the rela 4 and : r rad d ay connected to the nodes (A, B) in th board 2. s he If a c component ddemands mo than one relay to be c ore connected to the circuit, we separate the two o , e relay connection by the sig “:”. For example, “ y ns gn “R_1_1:8_10 E F 1 0 10k” means that, by s activating rely 1 on board 1 and rely 10 on board 8 a resistor with the va 0 alue of 10k oohms are going to be conne g ected betwee node E an F. en nd 1. 1 The DMM a oscilloscope connections are fixed and are n listed in the c and e e not component list. [14]
  16. 16. Figure 10 Components installed in the component b 0. e board  The fu function gene erator is con nnected to th node “A” internally th he hrough the r relay 1 on th source he board (board labe = 24) and its ground is hardwire to “0” th d el d d ed hrough the reelay 5 on th source he board it can be lis as “VFG d, sted GENA_24_5 A 0”1.  The nnodes of the second gro (X 1-X6 and the n e oup 6) node COM a not supp are ported in the current versio of the sof on ftware and m not be used in the component list. The pow supply t must wer terminals (6V, + +25V, -25V a COM) a connecte internally to the nodes (X1, X2, X3 and 0) respectively and are ed s X throug the relays (3, 4, 5 ad 2) on the so gh s d ource board (board label= 24)1. The power supp could e ply be connnected to th nodes of t first grou (A-I) by e he the up either one of the followi two ways: f ing  Shortcut w wires connec cting the (X X1-X3) node to the nod of the f es des first group ( (the node COM is ha ardwired to the node 0). For exampl figure 11 explains the internal co . le, onnection of the 6V DC pow source which will be describ V wer l bed in the componen list as nt “VDC+6V_ V_24_3 A”. Figu 11. Internal connection of the 6V power source using s ure l f r shortcut wires1.1 The describ matrix is the one connected a UNED. bed at [15]
  17. 17.  Single pole relays on componen board. Fo example, figure 12 e n nt or explains the internal e connection of the 6V DC power s n source, whic will be de ch escribed in the compone board t ent as “VDC+66V_24_3:10_ A”. 0_5 Figure 12. Internal c e connection of t 6V power source using sin pole relay the ngle ys For co omponents w more th two lead more rela are used and they ar mounted o the 20 with han ds, ays re on pin IC sockets. Fo example, the operatio C or onal amplifie shown in f er figure 13 ha 8 connecto Pin 1 as ors. and 5 are not connnected, thi operationa amplifier will be des is al scribed in th component list as he “OP_44_10:4_11:4 4_13 NC B D G NC C F N uA741” NC Fig gure 13. Operational amplifie connection er [16]
  18. 18. Figure 14 sho how a si F ows imple compo onent list cou look like uld e. Figure 1 Component list 14. t 2.2.2. Max lists x The T max lists are lists that describe a safe circu that cou be create and preve hazardou circuits s all uits uld ed ent usfrom being activ m vated. It is o only possibl to activate circuits th are safe according to a defined max list. le hat oEach list lists a n h number of so ources and c components and it descri ibes also how they can b connected to other w be dlisted sources or components if appropri relay sw d r iate witches are cllosed The max list forma is: at <Com mponent typ pe>_<Serial number> <Node1>< Node2><e l < etc.> <Va alue> The T serial nu umber is a se elected value to name th instrumen and the c e he nts components. There is no need to . oinclu the DMM set as volt ude M tage meter a the oscill and loscope in th max lists b he because they are high im y mpedanceand do not affect the circuit so much. Fi t igure 15 sho the max list of an op ows perational am mplifier circu uit. Figure 15 A max list for an operation amplifier circuit 5. nal [17]
  19. 19. 3. SOFT TWARE D DESCRIP PTION AN OPER ND RATION CYCLE VISIR is an open source project, w V e which offers a software distribution released un nder a GNU General UPubl License [ lic [10]. Thus, BBTH has assigned a web bpage [3] for its software developme and insta r e ent allation toallow other univ w versities and organizations to study its source and cooper d y e rate in its d development All the t.softw source buildings, p ware packets and i information are available in this web e bpage. This chapter desc cribes theVISI operation mechanism and the software fu IR n m unctionality and of eac part and its source building chregaardless to its version as it could be up t pdated frequ uently. To T get an ove erview of ho VISIR w ow works, imagine that you have a PC c controlling y your PXI insstrumentsand a breadboar with all th required c rd he components connected tthrough relay If you se comman to the ys. end ndsrelay to determ ys mine which relay should be connec d cted and whhich should not, you w build the desired will ecircu If you se comman to the PX instrumen terminals to determin to which node they s uit. end nds XI nts s ne should beconnnected, you w manage to see the results on your PC. The relay switc will e e ching matrix acts as a ro x obot whoreceiives the com mmands sen to the rela as well as the ones sent to the PXI instru nt ays s e uments termi inals andinter rprets them t a physical wiring as sh to l hown in figu 16. In view of that, t relay swi ure the itching matri should ixhave an interior connection between com e b mponents, noodes and ins struments. It receives the commands from the ePC ((through USB as shown in figure 16 B) n 6. Figur 16. An overv re view about how VISIR works w s Software func ctionality an its source building are going to be discussed a nd e e according to the whole o o operation hanism proc starting from the client login till receiving th results ba on the cli screen.mech cess l he ack ient [18]
  20. 20. 3.1. We Interfac eb ce It is the webp t page of VISIR through w which user c access t the experi can to iment client, it is written in PHP , nagain MySQL and installe in the w nst ed webserver as ssigned for VISIR. It h handles all t client lo the og-in andauth hentication procedures ov HTTPS protocol. W ver When a client logs in, it generates an experimen session t n ntcook with the client charac kie cteristics (stu udent, teach priority, IP address. etc.) and sto it in the database her, oresto be recalled by the measur e y rement serve for authent er tication purp pose, Figure 17. Figure 17. VISIR web inte erface 3.2. Exp periment C Client It is a packag integrated in the VISIR webpag and creat by Adob Flash. It represents t entire t ge ge ted be thelaboratory work kbench (with all its instr h ruments, commponents an breadboa simulated through a HTML nd ard d) anpage as an emb e bedded object. Client is free to cho s oose the ins strument mo odule with wwhich he is familiar srega ardless to its model or manufacturer as shown i figure 18. By this wa it is possible to use a virtual m r in ay,front panel dep t picting one- -instrument model to c control a d different instrument moodel as long as the gperfo formance of the real inst trument is eq qual or bette than the p er performance of the depi e icted instrum ment. Theavail lable module are: es • Tradittional breadb board. • Defau PXI-instru ult uments inter rfaces of Nat tional Instru uments. • Digita Multi-Met (Fluke 23 al ter 3). • Functtion generato (HP 33120 or 0A). • Oscill loscope (Agi ilent 54622A A). • DC Po ower Supply (E3631A). y [19]
  21. 21. Av vailable mod dules Selected modules d Fig gure 18. Client selects availa modules t able However, oth modules could be bu with Ad H her uilt dobe Flash. AAfter choosi the prefe ing erred modul client les,start to wire the circuit wit the mouse and with t available componen in that se ts th the e nts ession, and a adjust hisinstr ruments as if he was loc f cated inside a real labor ratory. Figur 19 shows the virtual w re workbench o VISIR ofwher all the in re nstruments teerminals and componen list are available to de d nt esign the de esired circuit All the t.time spent in des e signing the c circuit, the c client is occu upying his ow PC not th real instru wn he uments. Use manual erdocuumentations are available at the project website [2]. Figure 19. Virt F tual workbench of VISIR h [20]
  22. 22. When the client clicks on the com W mponents but tton as show in figur 20, a pul wn re ll-down men of all nuavail lable compo onents is shoown. This m menu can be configured and modifie through t “library.xml” file ed thelocat in the sa location of the “brea ted ame adboard.swf file, in the experiment client packa within th VISIR f” e t age hewebppage source (to be discu ussed later in the installat n tion chapter) ). Fig gure 20. Pull-d down compone list menu ent When the cl W lient gets hi circuit rea and clic on the (perform ex is ady cks xperiment) button, the c b client PC(exp periment clieent) starts t call the “ to “measureme server” (see the ne section) through ex ent ext xperimentprotoocol. The ex xperiment pr rotocol is an XML based protocol, w n which use eeither XML Socket API or HTTP Srequ uests to trans sport the req quest data to the measur o rement serve The expe er. eriment proto ocol transmi all the itsinstr ruments adjuustment and configuratio and the circuit design through an XML messa For exa on n n age. ample, anexpeeriment proto request sent by a 54 function generator c ocol 411 n could look lik ke: nctiongenerat<fun tor> g_waveform value="sine" /> <fg " <fg g_amplidute value="1000 /> 0.0" <fg g_frequency value="1000 /> 0.0" <fg g_offset value="0.0" /> <fg g_startphase value="0.0" /> e <fg g_triggermod value="co de ontinous" /> <fg g_triggersource value="immmediate" //> <fg g_burstcount value="0" /> t / <fg g_dutycycle vvalue="0.5" / /> <fg g_userdefineedwave lengt th="20" enco oding="BASE E64">ABCD12 234ABCD1234ABCD</fg g_userdefined dwave></functiongenerator>. [21]
  23. 23. Web W services prescribe XML based m X messages co onveyed by I Internet protocols such as SOAP to b sent to a bethe “measureme server”. TCP/IP on p 2324 d “ ent port does the con nnection curr rently. Henc Experime client ce, ent(web server) co b ould run on a separate machine. T XML b n e The based protoc describe what sett col es tings andfunc ctions each instrument type can perform, independent of hardware manufacture that’s w f er, why, it isposs sible to selec an instrum ct ment simulat module i ted independently on the ma anufacturer, also it is po ossible tocreat new modu of instru te ules uments that d not exist in the curren set. do nt 3.3. Measuremen Server nt It is a softwar program written for M t re w Microsoft W Windows in C C++ using M Microsoft Vissual C++. It receives tthe m measuremen requests fr nt rom the expperiment clie each req ent, quest is sent in a separat TCP sessi te ion, thus,conn and disc nect connect are required for every reque made to t server. T requests/ r est the The /responses sh hould notexce 64 KB in size. Figure 21 shows a running me eed n e easurement server on a M Microsoft wiindows systeem. Figure 21. Mea F asurement server running The T role of th measurem server c be define in four ma steps. he ment can ed ain 1) Authhentication: At each req quest, it verifies that the client is a v valid user by validating t client y the cook generate by the web server agai the data kie, ed b inst abase. 2) Validdation: It ac as a virtu instructor it compare the receiv circuit da with the max lists cts ual r; es ved ata before sending i to be exec it cuted on the real instrum e ments, to avvoid any dammage to inst truments. The max lists ar created b the admin re by nistrator (tea acher) to de efine the per rmitted valu of the ues circu componen and instr uit nts ruments. Thi lets him to be the only responsible for any dam is o y e mage. 3) Time e-sharing: It can handle requests fro 16 simul e om ltaneous clie with less than a seco (1/16 ents s ond second is the ma aximum time for each re e equest) by qu ueuing all simmultaneous rrequests and perform d them sequentiall with regar to priority reservation etc. m ly rd y, n, 4) Cont trol: After v validating an queuing th requests, it starts to h nd he handle them either direc using m ctly GPIB module or sending them sequ B uentially ove TCP/IP through the port 5001 to the er e “equuipment serv ver” (see the next section). In the se e econd case t measurem the ment server acts as a gatewway and co ould serve more than one equipm ment server. As it com mmunicates with the equippment [22]
  24. 24. 3.4. Equ uipment S Server It is a stand- t -alone equip pment contro oller, handli low-leve instrumen interfaces and hostin all the ing el nt s nginstr rument hard dware togeth with the relay swit her e tching matr rix. It is div vided into t three parts, the PXIplatf form, the rel switchin matrix an the PC th handles t commun lay ng nd hat the nication amo them wi server ong ithsoftw installe in it. The server softw is writte in LabVIE Figure 2 And all th instrumen drivers ware ed ware en EW, 22. he ntinsta alled in the L LabVIEW are IVI (Interch e hangeable VVirtual Instru uments) com mpliant [11]. Figu 22. Equipm server soft ure ment ftware running The T equipmen server rec nt ceives a validdated sequen ntial experim protoco requests fr ment ol rom the measurementserve in separat TCP sessions over TC er te TCP/IP throu the port 5001 and ex ugh xecutes it th hrough the c connectedinstr ruments. Aft that, the results retur back to th client scre with the same sequence. The re ter rn he een e esults arerepreesented in fo of measu orm urements on the virtual i n instruments.. Most of undergraduate electronic la M e aboratories o all the un of niversities a around the world have common wequipment (osc cilloscopes, Function g generators, multi-meters DC pow supplies and brea s, wer s, adboards) ardless of threga heir model and manuf facturer type. The curr rent VISIR supports P PXI, however, otheruniv versities wou like to u another platform (L uld use LXI, GPIB, etc.). To en nable interch hangeability betweenworkkbenches an different grid nodes ( nd g (different un niversities), V VISIR recom mmends fun nctions and a attributesdefin by the I Foundat ned IVI tion [11] to be used to describe the base class capabilities and class e e s extensioncapa abilities of th lab hardw he ware. Accordingly, it should b possible to create a standardize approach which is easy to ado Base A be ed h, opt.capaabilities are t functions of an instru the s ument class that are commmon to most of the instruments avaailable inthe class. For ex c xample, for a oscillosco the base capabilities mean edge triggering o an ope s only. Other t triggeringmethhods are def fined as extension capab bilities. The f functions su upported by t VISIR oscilloscope are listed thein ta 3. able [23]
  25. 25. Tab 3. The VISI oscilloscope capabilities ble IR e Grou Name up Description D n Base Capabili ities of the IviS Scope speciification. TThis group includes the p IviSco opeBase capabbility to acq quire wavefforms using edge triggeering. Extennsion: IviScope with the abilit to ty IviScopeWWaveformMeas calcu ulate wavefo orm measur rements, su as uch rise t time or frequency. Extennsion: IviScope with the abilit to ty modi ify the be ehavior of the trigg gering I IviScopeTrigger Modi ifier subsyystem in th absence of an expe he ected triggeer. Extennsion: IviScope with the autom matic IviScopeAuto- Setup configuration ab bility. The T goal of th IVI Foundation is to support 95 p he percent of th instrumen in a partic he nts cular class. T VISA The(Virt tual Instrum ment System Architecture standard [12] is accep e) pted too but the instrum t ment function should nsbe th hose defined by the IVI standard. Fi d igure 23 exp plains the fle exibility (pro ovided by IV of selecti of the VI) ionfront panel and the platform tal d m. Figure 23. The role of IVI in the frontal panel a the platform selection and m After understanding the software f A function of each part s sequentially, we can su , ummarize th whole heoper ration proces as shown in figure 24. ss . [24]
  26. 26. Figure 24. Overall operation process of VISIR u l o [25]
  27. 27. 4. INSTA ALLATIO ON Before startin with the installation an overvi B ng e n, iew on the connection is given. A mentione in the As edprev vious chapter the web se r, erver, the meeasurement server and th equipmen server sof he nt ftware, each could berunnning on a sepparate comp puter and the can comm ey municate wit each other by TCP po th r orts. At UNE all of EDthese servers are running on the same m e e n machine (NI PXI-Contro I oller), however, they sti communic with ill cateeach other throu TCP por The hard h ugh rts. dware compponents shou be conne uld ected properl before sta ly arting theinsta allation. All the matrix cards should be connecte properly t their corre c ed to esponding in nstruments in the PXI nplatf form. The co omponents a distribute on the co are ed omponent bo oard. The mmatrix is conn nected to an external n(12 V) dc power source and to the controller through a USB cab A PC scr V r h ble. reen, a keybo oard and a m mouse areconnnected to the controller. Figure 25 s e show the VISIR connect tion at UNE Windows XP is the o ED. s operatingsyste of the co em ontroller. Figure 25. VIS connected at UNED SIR To T understan the instrum nd ment connec ctions, figure 26 and 27 explain the internal con e nnection bettween thePXI- -Instruments and the vi s irtual board After chec d. cking all th connectio he ons, software installation can be e nstart Coming up next, the step by step installation process. ted. e p n [26]
  28. 28. Figure 26 Connection o the DMM an the oscillosc 6. of nd copeFigu 27. Connec ure ction of the DC power supply and the functi generator C y ion [27]
  29. 29. 4.1. Lab bVIEW LabVIEW is the platform with which the equipm server s L m h ment software is d developed. It must be ins t stalled onthe machine tha runs the equipment se m at erver softwa The equi are. ipment server software that include a relay esswitc ching matrix version 4 is compatible with LabVIEW v 4.1 version 8.6 or higher. LabVIEW l license ispurc chased from N National Ins struments [13]. LabVIEW 2010 is the version ins W stalled curre ently at UNE ED. 4.2. NI D Device Dr rivers All A the NI PX XI-Instruments (DMM, Oscilloscop DC Powe Supply an Function Generator) mounted pe, er ndin th PXI chassis and described in t equipme server software mu be define in the L he the ent ust ed LabVIEWplatfform. The N device driv comes w the Lab NI vers with bVIEW licen however it is recomm nse, r mended to install thelates NI device driver versi from the National in st ion e nstruments w webpage to mmake sure th it contain all the hat ns 1funcction files (.v files) nee vi eded to run the equipm ment server s software. Ni device driv i vers version released nAug 2010 [14 is the vers gust 4] sion currently at UNED. T check the installed devices in the LabVIE platform go to star menu P To e EW m, rt Programs NationalInstr rumentsMMeasurement & Automati Explorer In Devices and Interfa ion r. s faces, if you click the dro op-Downmen beside the PXI chass all the i nu e sis, installed instruments wi appear w their rel ill with lated slot nuumber asshow in figure 28. wn Figu 28. Instruments defined in the Measurem & Automa ure n ment ation Explorer 1. 1 The “.vi” files for each inst trument are requ uested to execute the equipment server. They are found inside th “inst.lib” and the “vi.lib” e e he d folders, both folders are fou within the La h und abVIEW installaation folder. [28]

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