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1. Limitations of Use The Council of the University of Southern Queensland its Faculty of Engineering and Surveying and the staff of the University of Southern Queensland do not accept any responsibility for the truth accuracy or completeness of material contained within or associated with this dissertation Persons using all or any part of this material do so at their own risk and not at the risk of the Council of the University of Southern Queensland its Faculty of Engineering and Surveying or the staff of the University of Southern Queensland This dissertation reports an educational exercise and has no purpose or validity beyond this exercise The sole purpose of the course pair entitled Research Project is to contribute to the overall education within the student s chosen degree program This document the associated hardware software drawings and other material set out in the associated appendices should not be used for any other purpose if they are so used it is entirely at the risk of the user Prof G Baker Dean Faculty of Engineering and Surveying 154 ENG4111 4112 Project Reference Book B Certification I certify that the ideas designs and experimental work results analyses and conclusions set out in this dissertation are entirely my own effort except where otherwise indicated and acknowledged I further certify that the work is original and has not been previously submitted for assessment
2. 2 long 3 signed 4 unsigned The first two of these modifiers change the number of bytes allocated to the data type it is used in conjunction with The last two deal with weather or not the most significant bit is used as the sign bit if it is 1 the number is negative and 0 is positive 23 The following table shows the ranges of variables if the modifier is used Data Types Num of Bytes Range short int 2 32 768 to 32 768 unsigned short int 2 0 to 65 535 unsigned int 4 0 to 4 294 967 295 int 4 2 147 483 648 to 2 147 483 648 long int 4 2 147 483 648 to 2 147 483 648 signed char 1 128 to 127 unsigned char 1 0 to 255 float 4 Increases accuracy double 8 Increases accuracy long double 16 Increases accuracy Table 5 2 Effects of modifiers and data type size The way that a variable is as follows int variable name long int Variable Name Note that the C language is case sensitive so in the above example two separated variables will be created The size of the variables are dependent on the system that the programs is compiled on Because of this a method of determining the size of a data type is required especially for dynamic memory allocation In C the function sizeof variable does exactly that it s usage is as follows size sizeof variable This will return an integer variable which is the number of bytes that the data type occupies By using this function then programs can be wri
3. Connection GPIB Interface PC with GPIB Interface card pages allow the user to enter data to change settings on the programmable instrument Once the data is retrieved by the web server it is passed onto an application This application then uses this data to determine the changes to the Instrument that the user desires The program uses the SICL API to communicate with the device and the desired setting are enforced For the purpose of detecting problems the device is queried and the results of this query are check against the data sent by the user The application is then responsible for replying to the user and must do so in the form of a HTML code This response will be displayed to the user as a web page and will inform the user if their request was successful or not Because of the modular structure of this implementation the division of devices can be done using separate web pages for each device and even for the different device sub commands The way that this is done is up to implementor and is easily changed 19 making the system easily maintainable Each web page has one or more corresponding CGI program that is responsible for carrying out the changes on the programmable instrument that it corresponds to If the ATE rack is upgrade or a device is replace then it is possible to alter the system with minimal effort Also the addition of providing advanced features such as sequencing this could be done via separate web
4. O OAN OAT FF wWNY el es ao fF WN FO lt meta name description content Provide remote access to ATE equiptment gt 16 17 lt gt 18 lt 150 pixels remainder gt lt warning if only a single panel gt 19 lt do not use nested frameset environment gt 20 lt 10 percentage gt 21 lt gt 22 lt gt 23 lt gt 24 25 lt head gt 26 27 lt frameset cols 300 border 5 gt 28 lt frame src Frames_files NavPanel html name Nav gt 29 lt frameset rows 85 15 gt 30 lt frame src Frames_files Project html name Upper gt 31 lt frame src Frames_files Static html name Lower scrolling no gt 32 lt frameset gt lt frameset gt 33 34 lt noframes gt 35 lt BODY gt 36 lt P gt This document uses frames lt p gt 37 This is in the noframes section 38 lt body gt 39 40 lt noframes gt 41 42 lt html gt 43 The code for this page was obtained from 13 and altered to suit need of this desired imple mentation The important section of this code is lines 28 33 as this section is responsible for the division of the page into frames The frameset tag is used to specify the sections containing the information about how the page is to divided this division can be vertically using the cols option or horizontally with the rows option The size of the divisions are specified with the option used and can be expr
5. The Standard Commands for Programmable Instrumentation is the most recent attempt to provide compatibility between Programmable Instrumentation from different manufactures this is topic of 15 This standard defines specific commands that each instrument class must obey if followed this will provide complete compatible and configurable systems among these instruments 2 2 Type of IEEE 488 Cards Available Currently on the market there are many manufactures that are producing IEEE 488 1 and 488 2 cards for interfacing with programmable instruments Some of the major manufactures being National Instruments and Agilent Technologies Inc Each of which are compatible with the different instrument manufactures due to the standards specifications and each with their own system drivers and API libraries Currently there are a few different interconnection methods between the interface card and programmable Instrument The main ones being the CN24 connector and cable that uses a 24 pin connector and cable with 24 wires the RS232 and Universal Serial Bus USB The Last two connection methods are not commonly used as they are serial connections and the ASCII characters used by the IEEE 488 standard is more suited for a Parallel transfer media such as the first method Appendix C contains the various GPIB in terface card produced by Industrial Automation Products and the card used in this project The speeds that the serial communication can obtain is le
6. 33120A Function Arbitrary Waveform Generator Select Waveform Type Sine Triangular Square Ramp Frequency Peak To Peek Voltage Sweep over a range of frequencies From To Press to Submit Not Sure if this frame will be kept the sequencing in this manner would reduce the size an complexity of the CGI programs that are responsible for each step This structure would also make it possible to use the individual components in a various number of sequences and each step would be easily maintainable Alternatively the implementation of sequencing could be done via the use of a page with the individual steps all listed with the submit button only available for the step currently available Through the use of a complex CGI program for each step a web page with the submit button for the next step being returned after the changes have been implemented This manner of implementing the sequencing has the advantage of stepping the user through the step automatically the main disadvantage of this method is the cgi cannot be used for another sequence If a new sequence was desired then a new web page and corresponding CGI programs would need to be created Another aspect of creating web pages for the ATE devices is the type and num ber of settings that should be implemented on each page For some devices such as the Power Supply using one page to contain all the possible settings is sufficient But in the case of oth
7. an on board network card and a PCMCIA network card One of the Network Interface Card NIC was given an address of 192 168 0 1 and the other 192 168 2 1 and an entry was entered in the routing table of this PC so that information from one network to the other was passed to the correct interface device Two PC s where connected to the laptop through the use of two network hubs and each PC assigned an IP address that was from the same network of the NIC device of the laptop connected to the same hub The system was tested using the ping command and it was found that each host was reachable through the router Now the same test as previously used was duplicated except the IP address was 192 168 0 2 and the PC being used was on a different network The system was also proven successful under these circumstances There was no noticeable delay due to the router but this was expected as on the Internet usually more than one router exists and the networks are processing more of a load So from these test it is expected that the system will operate correctly over the Internet Of course a much longer delay would be expected but not enough to effect the system s performance This is due to the fact that more routers would be traversed and the propagation delays caused by the communication media the usual round trip time is around 200 ms This would be noticeable but the system only sends a small amount of data and would not be expect to cause the
8. example of this is shown in the figure 10 Figure 9 2 Apache Installation 2 Apache HTTP Server 2 0 Installation Wizard Server Information Please enter your server s information Network Domain e g somenet com laptop com Server Name e g www somenet com www laptop com Administrator s Email Address e g webmaster somenet com admin laptop com Install Apache HTTP Server 2 0 programs and shortcuts For for All Users on Port 80 as a Service Recommended O only for the Current User on Port 8080 when started Manually 57 9 2 General Configuration Most of the configuration settings that relate to the operation of the web server are done via the httpd configuration file This file is located in the confs directory which is in the directory that the server was installed to This file is a text based file that is read by the server during loading An example of some of the configuration changes that are handled by this file is the location of the web pages and the cgi programs This allows the user to specify any directory that contains web pages that will be accessible for users This configuration file is divided into three sections 1 Global Environment 2 Main server configuration 3 Virtual Hosts The Global Environment allows settings such as the root directory where log file and configuration files are located Also certain aspects of the operation of the web server can be changed v
9. functions The printf function can be called to print either a constant string that the pro grammer hard codes in a variable within the program or a combination of the two The code below shows an example of each printf This is a Constant String n printf d AfXAn int_var float_var printf The integer variable has the value dAn int_var From the examples above we can see that the printf function requires 2 argu ments The first is the string that will be printed this string must contain formating identifiers and control characters An for new line And the second argument is the list of variable that correspond to the format identifiers Care must be taken to en sure that the variable names are in the right order otherwise incorrect data will be printed The scanf function is as follows scanf d amp int_var 29 This shows that the scanf function also requires two arguments the first tell the function what type of data is expected and the second argument is the variable that the data will be stored in The important thing to note is the use of the ampersand operator this operator in C means the address of and is important for the function to know the memory address of the variable 5 3 2 Using files for I O C allows the user to use files for input and output and does so in a similar manner to the standard I O functions The only difference is that an ID for the file is needed and is cr
10. in any other course or institution except where specifically stated My Full Name Student Number XXXXXXXX Signature Date Figure 11 3 The required text and layout of the Certification page of your dissertation Substitute your name and student number as indicated and reproduce the text exactly as shown here Acknowledgements The assistance received by continuous meeting with one of my supervisor David Parsons through the duration of the project aiding in the various aspects of the ATE equipment and the direction of this project Also for acquiring and passing on of information relevant to this project The assistance received by supervisor John Leis with regards to the different as pect of this project and possible solutions The assistance received by laboratory technician Terry who helped with gaining access to the ATE equipment and assistance when problems where encountered My partner Rebecca who tolerated me through this stressful time and got me coffee vi Contents 1 Introduction 1 2 IEEE 488 General Purpose Interface Bus 3 2 1 History of IEEE 488 Standard ss als et a eee ee ee 3 2 2 Type of IEEE 488 Cards Available 00 4 2 3 IEEE 488 Connector and Wire Configuration 5 2al MALAS ds a te a a OEA A a 6 Ave gt ransi n Busy T e tau a ide a oan ow Renin ee Bee A EA 6 2 3 3 Management Bus a oi dae be Aa Se Bates ee eee 7 2 4 IEEE 488 Conn
11. may also be assigned to each device also ranging from 0 to 30 but this address is optional and is usually not T assigned The cables that link the devices is a shielded 24 wire cable and the distances al lowed by the standard is either 20 meters or 2 times the number of instrument connected to the bus whichever is smaller The speeds that are achieved by the GPIB standard are in the range of 250 Kbytes sec to 1MBytes sec note it is in Bytes sec due to the fact that the 8 data bus line When considering the operating speed of the interface bus the cable size must be taken into consideration if high speeds are desired the the length on cables used to connect the devices and interface card must be small The pin allocation is depicted in the following diagram Figure 2 2 IEEE 488 CN24 Connector Pin Configuration From the diagram and Green 5 it can be seen that the 16 signal wires are broken down as follows Data Bus DI01 DIOS Data bus Management Bus Ten REN Remote Enable Synchronous EOI End or Identify Signals ATN Attention IFC Interface Clear SRQ Service Request Six Transfer Bus Asynchronous NRFD Not Ready For Data Signals NDAC Not Data Accept Twisted Pairs DAV Data Available This shows how the IEEE 488 standard handles the transfer of both synchronous and asynchronous data 10 Chapter 3 Application Programmers Interface Libraries An Application Program Interface as defined by w
12. multiple Web Pages to be displayed at one time Using this structure the developer can use one of the HTML pages as a navigator to the other pages This is the method used to provide access the the different programmable instruments in the ATE rack The following figure displays the main page designed for this project and the code after the figure shows how a form is created 49 Figure 8 3 HTML Frames 3 simpte Pe z macrason pavo ron O O AAG Pu gro O BS 4 13 Address A rerputz7 0 0 trames dome Remote Access to Test Equiptment Thus Site provide remote access to the Automated Test Equiptment Rack m the 2222 lab of the Univernty of Southern Queendland The devices are accessed wia the links on the side namgation panel clicking on the link opens the page for the demce The settings that are to be changed are entered in the appropriate feilds and are performed by pressing the submit buttonl Not Sure if this frame will be kept lt html gt lt head gt lt DOCTYPE HTML gt lt A Basic HTML Frames example gt lt Nathan Hetherington 2004 gt lt title gt ATE Remote Access lt title gt lt this is for use by web search robots gt lt keywords is used for searching gt lt description is the summary returned gt lt meta name author content Nathan Hetheington gt lt meta name keywords content html gt 50
13. that comes with the apache server called htpasswd This application is executed with three arguments the first is the options that the user wishes to enable secondly is the file that will store the user password information created and last is the user that will be entered into the file The basic operation of this application is as follows htpasswd c usr local apache passwd passwords username The user will be prompted to enter the password this will cause the creation of a 99 file in the specified directory This file contains the users name and the encrypted version of the password this is so later authentication can be achieved by comparing the encrypted version of the enter password with that in the file Note that the c flag is only use to create the file if a user is to be added to an existing password file then this flag is submitted This is very important as using the c flag will cause the file to be overwritten Care must be taken in the placement of this file as it contains password informa tion that could be used to guess the actual password For this reason this should be placed in a directory that the http server cannot access Also the permissions of the file must be set to allow access by the web server user hence deny access to other users After the password in created and placed in a directory then the configuration files must be set to use this newly created password file This is done by creating and placing a f
14. the user to inform on the status of their request If the settings of the device where successfully changed then a web page stating that the settings have been applied will result If the program fails then the user is informed to try again There are nothing that the user can do if the problem is with the hardware in this case an error file is written and it is up the administrator to check this file Later implementations may sent an e mail to the lab technician informing them that an error has occurred 42 7 7 Compiling Device Programs When compiling programs that make use of the SICL library then some sets must be taken First is the inclusion of the sicl h header file which contains the prototype definitions of the functions provided by the library And finally is informing the link which library file contains the machine code for the functions defined in the header In the case of this project sicl32 lib was the appropriate file 43 44 Chapter 8 Creating Web Pages for Remote Access The Hyper Text Mark Up Language is a plain text based language and can be created edited or viewed using a simple text editor on any computer platform HTML is similar to a scripting language as the web browsers reads the HTML file and determines the way of formating the data from the code This makes HTML multi platform as long as a web browser exist for that platform Also with the modular structure of the web browser this allows for differ
15. 1 1 Basic Data Types Within C there are a few data types and the user can define their own each of which are used to associate the data stored with it s meaning and method of processing A table below shows the various data types the amount of memory they occupy and the type of data stored in them There are three basic data types 1 char ASCII characters 2 int Integer numbers 3 float Floating point numbers 4 Pointers Stores memory addresses The type of data that can be allocated to each variable is enforce by the compiler so that unintentional assignments don t result data loss and hard to find bugs The use can force the allocation of a variable into a different type via type casting this is done by placing a data_type in front of the variable to be converted 22 For example int var int float_var This will cause the floating point variable to be converted to a integer variable and assigned to int_var Data Types Num of Bytes Variable Example char 1 a g b A G int 4 1 2 7 8 12 float 4 1 2 20 4 100 3 Table 5 1 Basic Data Types and Sizes These data types can only hold a certain range of values for integers this is 2 147 483 648 to 2 147 483 647 If this range is to short for the desired variable then a modifier that increases or decreases the number of bytes used by the data type can be used There is four of these modifiers available in C C these are 1 short
16. C The C programming language allows the user to read and write to what is referred to the stdin Standard Input and stdout Standard Output This standard input and output is by default the keyboard and monitor respectively but C also allows the user to specify a file or some other I O device The interfacing with I O is done via functions provided by the C standard libraries such as stdio h and stdlib h or API libraries for the I O device such as the sicl h and visa h libraries for this project 5 3 1 Standard I O with keyboard and monitor There are a few functions provided by the standard C libraries that read from the keyboard their use depends on the type of data desired Two such functions are scanf and gets the first obtains a single variable of the type specified and the second is used to 28 23 24 25 26 27 28 29 30 31 32 33 34 get a string of characters The output is handle by the one function printf and prints the contents of the variables passed to it the way the variable is interpreted depends on the variable format identifier used The following is a table of some of the format identifiers available Format Identifier Variable type Ad Yi Decimal signed integer O Octal integer Mx YX Hex integer You Unsigned integer YC Character s String Zot double He YE double ye G double p pointer n Number of characters written by this printf Table 5 3 Format Identifiers used with I O
17. URL For example ac cessing the URL http server edu stuff cgi_program query_string sends the data in cluded in query_string to the HTTP server running on the machine server edu 2 POST the data are sent as a message body that follows the request message sent by the client to the server This is more complex than GET but allows for more complex data This method uses Standard I O to pass the data to the application 35 Looking at the examples in Appendix E 1 it can be seen that the get method uses environment variables to pass the data to the application The application then reads the environment variables by using the getenv function This function requires the name of the environment variable to be obtained and returns the contents of the contents of the environment variable specified by the argument The environment variable that is on interest in the get method is QUERY_STRING this is a string that contains all the information from the web page that the application is to process The format of this string is the same no matter weather the GET or POST method is used and is as follows TEXT LINE ONE some text amp TEXT LINE TWO default value amp TEXT LINE THREE 1234 amp PASSWORD _FIELD secret The sections in capital letters are the names of the input fields on the web page the field name and value are separated by the character and any white space is replaced by a character Each of the separate fields are s
18. University of Southern Queensland Faculty of Engineering amp Surveying Remote Access of Automated Test Equipment A dissertation submitted by Nathan John Hetherington in fulfillment of the requirements of ENG4112 Research Project towards the degree of Bachelor of Engineering Computer Systems amp Bachelor of Information Technology Applied Computer Science Submitted October 2004 Abstract The control of Programmable Instruments using the GPIB is possible through the use of Application Programmers Interface API This thesis investigates the possibilities of using a web server to provide remote access to allow interactive control of the instruments in an Automated Test Equipment ATE rack Fully documented programs where developed using the Icc win32 software develop ment environment and tested using an Apache web server Programs and web pages where developed for all the instruments included in the ATE Rack A web server to host all the pages developed for interaction with the ATE rack was configured to provide a password controlled system But due to security issues regarding the PC that the equipment is attached to connection to the Internet was not possible But some tests where performed to simulate the various components that the Internet is comprised of to detect possible errors that may occur University of Southern Queensland Faculty of Engineering and Surveying ENG4111 2 Research Project
19. V5 0 that was being used to provide the remote access created a security hole in the Universities firewall The way that the software operated required 17 that a software port be left open so the server could listen on this port for any attempts to connect Hence for correct operation this required that the Firewall did not block this port As stated by 2 having any open ports exposes you to potential attacks that might exploit known or yet unknown vulnerabilities this page also contains links to sites the help identify open ports The vulnerabilities that 2 is talking about are those that exist either in the Op erating system itself or Trojan horses that have found their way onto the system In the case of the system that the HP VEE software was installed on the Windows 95 operating system is being used This operating system was designed when networking and the Internet where not very popular so the concept of security was over looked or undermined So as well as the software leaving a port open the OS on which it run could also jeopardize the security of the whole university network With this in mind one way around the firewall would be to use an application that uses a port that is allowed by the firewall That is exactly why for this project the web server based system was chosen as this application uses port 80 HTTP which is allowed by nearly all firewalls Also most web servers have the ability to specify the files that can be ac
20. anf fp d Bi From the examples above it can be seen that their use is exactly the same as to standard I O except for the addition of the file pointer All format identifiers and control sequences are exactly the same 5 4 Functions Within C this allow the user to write functions that perform some task and can be called by the user in a similar manner to those defined by the C libraries The advantage of this is that the user can write a function that performs a certain task and call it when desired instead of replicating the code each time the task is needed The following code defines a function that multiples two numbers of course a function may do more complex thing then this int mult int x int y int z 0 z x y return zZ From this we can see the basic structure of the a C function This first impor tant value is the return type of the function this tell what data type will be returned from the function The next is the name of the function and can be any name as long as it does not contain any of C s special characters Finally the last element of a function is the arguments this is the data that is passed to the function for processing There is no real limits on the number of arguments that a function can have but is up to the programmer to limit this to a reasonable amount The main function is a special case of a function but the same rules exist Fi nally if no return type or arguments are needed the
21. are various reasons for choosing Apache as a web server for both this project and web hosting in general This first is Apache s dominance in the web server domain this is illustrated by the graph shown in the figure below The only other web server that has a noticeable following is Microsoft s Internet Information Server which is shipped with Windows Server operating systems In addition to it dominance of the market Apache is also a cross platform web server This means that versions of Apache can be obtained for various operating systems such as Microsoft Windows Mac Os and Linux Unix From the view of this project this is beneficial as the system could be implemented in another Operating System inheriting their security and reliability advantages Probably the most appealing aspect of the Apache web server is the amount of On Line documentation and support that is available This is due to the fact that Apache is an Open Source program making it free to the public And because this software is open source this means that any software bugs and security holes are often detected and corrected much quicker then commercial products Apache can be obtained from www apache org and is free for download in various versions and platforms This site also contains a large amount of documentation for the installation and configuration of the apache server For this project an older version of apache web server was required this is due to the fa
22. ate the data label and actual data and the amp is used to separate the different data inputs So the programmer can simply step through the input string looking for the character Once this character is located then all characters between it and the next amp character is the data wanted In the CGI programs there is a function that takes the input string as the input argument and steps through the array of characters separating the various data The user is referred to the CGI program for the function generator the code for the function getVariables char Buffer This function will change from application to application and it s sequencing is dictated by the sequence on the data fields on the corresponding web page 7 3 Step 3 Obtain Device Commands The first step in the creation of the device command is to obtain the syntax of the commands that will be sent to the device The best source for such information is the User s Manual or Programmers Manual produced by the manufactures of the instrument For this project these documents where obtained from the Agilent Technologies web site Once the device settings being changed have been determined then the syntax of the command to be sent to the device must be looked up in the manual All commands are hierarchal this means that commands have subcommands that can be used in 40 conjunction to specify the exact setting of the device to be changed One example of this is the APPLy
23. atible system CGI programs can be written in a variety of programming languages The most used languages for CGI programs are C C Perl and Unix Stripting Languages BASH KORN etc If a language such as C C or Visual Basic are used then the program must be compiled and the resulting executable placed in the cgi bin directory of the web server In the case of scripting languages such as Perl which are interrupted languages rather then compiled the script can be placed directly into the cgi bin and an interpretor will need to be installed and functioning on the system It is worth noting that the interpreted languages will be slower than their compiled counterparts so if efficiency is of importance then a language such of 33 C C should be used 6 1 HTML CGI Program Calling Method The common way that CGI programs are integrated into web pages is to have a button that once click causes the application to be run The HTML code that does this must also specify the method which will be used for passing the information to the application The code below is responsible for this lt FORM METHOD POST ACTION cgi bin cgipost exe gt Code for data entry goes lt INPUT TYPE submit VALUE Press to Submit gt lt FORM gt This input is pretty self explanatory it consists of the method of input data and the application to run when the submit button is pressed The string in the action section co
24. buff The iprintf function can be used with two or three arguments and follows a simi lar format to the fprintf function for C The first argument is compulsory as it contains the device s identity that is used in the communication The second argument is the string that is sent to the device this string can be a constant string or composed of string variable as long as it follows the format that the device expects If the second argument contains variable then a third argument must be used and is the list of variable names that correspond to the format identifiers contained in the string The iscanf function is the similar to the C scanf function except for the addition of the session identifier The function will read the data on the GPIB and will store it in the variable passed to it the t format string specifies that an ASCII string will be read back The prompt function prompts the device with the string specified and then stores the response from the device in the variable in the fourth argument The same sequence of events could be achieved by using the printf followed by a iscanf but this function makes the process neat with only one line required Finally after all interactions with the device have been completed then the device session must be close just like a file in C This is done using the iclose method passing the session id as it s argument like follows iclose id For the purpose of assisting in the writing of re
25. cate with a device the programmer must create an interface session with the device The method to do this was outlined in chapter 3 where the open function is used to open a session and requires the address of the device In the CGI program for the 33120A device the address can be defined as a constant using the define mechanism in C define DEVICE_ADDRESS hpib7 10 This allows the programmer to use DEVICE ADDRESS whenever the actual de vice address is required during compilation this is replaced with hpib7 10 This is not compulsory but makes the code easier to understand and change later If the address of the device changes then only the definition string will need to be updated Using this address a session can then be opened and the resulting ID will be use when 39 communicating with the device At the completion of the program this session must be closed using the iclose function failing to do so will cause later run programs to act unpredictably Device Address 33120A Function Generator 10 54602B Oscilloscope 7 34970A Switch Unit 9 6624A Power Supply 5 Table 7 1 Addresses of Devices in ATE Rack 7 2 Step 2 Getting Data from Input String As mention previously the data that is enter into the fields of the web page are read into the program as one string So the application must separate the data from this large string The format convention of the input string is a is used to sep ar
26. cess by a user and also can implement password access The implementation is similar to that used by most web pages that obtain data and process it in some manner such as a database searches that the google search engine performs 4 2 Project Implementation Outline The concept of the way that the remote access will be implemented for the ATE rack is the Common Gate Way Interface Method which will be discussed in detail in chapter 6 But for now the diagram below shows the basic configuration of this method The diagram shows the communication paths between the different elements of this implementation At the centre of the system is the PC with a GPIB card this system could possibly contain multiple interface cards and is a detrimental part of the implementation The PC is responsible for the communications between the user via the Internet and the ATE rack via the GPIB card and is responsible for controlling and monitoring the access to the services that it provides The way that the PC performs these tasks is through an Apache Web Server that is installed and configured to provide the services described previously All configuration changes can be done via configuration file and are discussed in chapter 9 The web server allows the user to access web pages for interacting with the ATE systems and these web 18 Figure 4 1 Implementation of Remote Access using Web Server Web Browser ATE Rack Internet Connection Internet
27. command that allows setting to be applied on the device some of the sub commands are SINusoid lt frequency gt lt amplitude gt lt offset gt SQUare lt frequency gt lt amplitude gt lt offset gt TRlangle lt frequency gt lt amplitude gt lt offset gt RAMP lt frequency gt lt amplitude gt lt offset gt NOISe lt frequency DEF gt lt amplitude gt lt offset gt DC lt frequency DEF gt lt amplitude DEF gt lt offset gt USER lt frequency gt lt amplitude gt lt offset gt From the above examples the different are fields have the following meanings e Square brackets indicate optional keywords or parameters e Braces enclose parameters within a command string Default parameters are shown in bold e Triangle brackets lt gt indicate that you must substitute a value for the enclosed parameter So using the information contained above a string can be generated to change set ting can be generated This string can then be sent to the device and the desired changes will be made For example the following code will set the function genera tor to produce a sine wave with a frequency of 12Khz 2V peak to Peak and an offset of OV APPL SIN 12Khz 2V 0V Note that a semi colon is used to separate the different command levels and there is a space between the different input fields When this string is sent to the dev
28. created the indexing is the same as a single dimensional array except an index for each dimension is required 5 1 3 Structures In most cases it is common that different data types are required to identify an object for example a student may have a Name age Student number and grade point average So it makes sense to group this type of data into one entity this is the purpose of C structures and C classes The following code is an example of how a structure is created and defined as a new data type in C is as follows typedef Struct Student int age student_number char name 30 float GPA STUDENT After the structure is defined using the typedef function then the user can create a variable of this type in the same manner as a standard data structure The label assigned to the data types in the string after the right parentheses and before the semi colon in this case STUDENT The creation of a student variable is as follows STUDENT St1 26 After the variable has been created then each of it s elements can be access using the operator The following shows the student data type being used St1 age 18 strepy St1 Nathan printf Age is d n St1 age A full example program of the use of structures is found in Appendix C 2 5 2 Variable Scope One of the most important considerations whenever writing C programs is the scope of a variable The scope of a variable as defined by 16 is the range o
29. ct that the system that apache was to be installed to contains the Windows 95 Operating System Attempts to install new versions resulted in problems mainly due to 59 Figure 9 1 Market Share of Various Web Servers 702 Apache Microsoft Sun NCSA Other Sa 35 S j LO LO LO LO LO Pe fee fe fe 00 00 00 00 h h D S S oodd ddA NAN 0 00 00 00 O o T ADAAAAAMAAAAAMAAAAAHASSSSSSosSooosesoososooooocse A a a a a a a a E n E n Ad ini dtd dd dd de AAN SOSA SAS ASS NS SSA AS AS O AN PHELaAPSCLaeP Sts SCL ste Star Stas State Cts Sid ODBASAOGAASOGAsBOGASsoOGAdsOGsaA soGAasowGwW sadsowvgas om Crom CA Orn T OVC OM MT Oo TC Oo TC WO 7t oO Tt the fact that later versions are designed to take advantage of Thread technology The Windows 95 OS is not a true multi tasking OS and does not support the use of threads Also it is worth noting that using Windows 95 for a web server is advised against because of the security risks that the OS creates So for further development of the process developed by this project it is advised that a different OS is used for the system 9 1 Installing Apache As mentioned earlier Apache can be downloaded from www apache org or various mirror sites and can be obtained in binary or source form If the source code version is acquired then it must be compiled prior to installation The advantage of the source version is that in the compilation process it can be optimized for optimal performance on t
30. ction which specifies access to the web pages in this directory The AuthConfig option is used to activate the password access after all these steps are done then the web server must be restarted 9 4 Adding Web Pages and CGI Programs After the web server has been installed and configured as desired then adding the contents of the web page is simply a case of placing the files in the correct directory In the case of the html pages and cgi programs this is the directory specified using the lt Directory gt The defaults for these fields are the htdocs and cgi bin directories located in the directory where the web server was installed on the system Once the files have been placed in their correct directories then any links or references to these files in the HTML pages must be updated to reflect there current placement 61 62 Chapter 10 System Test The testing of this system was simply a matter of seeing weather it worked under certain circumstances as there are no real other measurable performance aspects The system must be test in a manner that would simulate it s normal operation if implemented in the real world If operation under these circumstances then there is no reason why the system would not operate correctly through the Internet The ideal way of testing this system would be to provide the remote access sys tem to be accessible via the Internet But this was not possible due to difficulties imposed by the in
31. e Bale eel Gee 100 E 2 2 Oscilloscope 2 A oe nae a a Ok ee A eg 107 E 234 OWI WT x of Poh eh a aes a ake Pe eee Plows a 113 Ei Power Upper eta e tape ea GO E e g 121 F Basic C Programs 127 ix El Data Types ta de e ds de aad a NA NAO da 127 A A A pte re Pe ene hohe ks es 128 Huge Variable Scope pa ibe iS a ADA OR AE ee EA 129 F 4 Input Output Example 8 ere ae eth lat Rn NE Pend BG te Bias A 129 Application Interface Library 131 Cl VISA LABIAL coto ary ds Hal ew A OR EE RE ek R S 131 C2 SICE LIBLATY tess ee oe a os ie a Bo Ss ee hd Es ee aaa eth ea is 255 Device Manuals 345 H 1 Function Generators 242 4 fda ke Pb ade PB ee ee ee 345 H 1 1 Quick Referentes s 2 2 0 to a See a ee be Se ee ee 345 12 Oscilloscope so ia bese A bee ee BS 356 MUA yl eo attain shah aro hes 4S cee Meri AA cae teas acess Dk 413 H4 Power A es ods KES Sol el E Oe es Bie O58 434 Chapter 1 Introduction The objective of this project was to develop a method of providing remote access between a users computer and the devices in the Automated Test Equipment rack This access method was to be in a manner that overcomes some of the problems with the system that was investigated previously In completing this project the following steps had to be achieved 1 Interface card had to be identified 2 Application Programmers Interface Libraries had to be obtained 3 Device command had to be Identified 4 Programs that Interface with device had to be wr
32. eated using the fopen method and after used the file must be closed using the fclose These functions are used in the following manner FILE id id fopen Filename tzt r In order to read and write to files a pointer to the file must be created this pointer is type FILE and is defined in the stdlib h C library Once a pointer of this type is created then the fopen method is used to link the file to the pointer and it requires two arguments The first of these arguments are the file name that is in the form of a string this string can be hard coded in of enter by the user into a character array The second argument is the mode the file will be opened in and there are a few different modes that can be used when accessing a file they are as follows Format Identifier Variable type File Created If File Exists a Appending Yes Append to a Reading and appending Yes Append to r Read only No If not found returns NULL r Reading and writing No If not found returns NULL Ww Write only Yes Overwritten w Reading and writing Yes Overwritten Table 5 4 fopen File modes After the file has been linked to the pointer then the file can be written to and read from These task are performed using the fprintf and fscanf which are similar to the function for standard I O except they require file pointer The Examples below demonstrate this 30 forint ID Number d t d n i 1 scorefi fsc
33. ection Details aia ce a ye A ASA T7 3 Application Programmers Interface Libraries 11 3 1 Standard Instrument Control Library oaoa a a 11 gold SICE ima AA aw E 12 3 2 Virtual Instrument Standard Architecture 14 4 Remote Access Implementation Method 17 dal Projet Back round ets o arte e air dl WET cas SiG t 17 4 2 Project Implementation Outline es ws he Gow e ee ee 18 5 Writing C Programs 21 5 1 Data Types and Structures bak SO de OU A Ow a eG 22 Dalek Basie Data Types s sorz g es a ar es Sk si A a AD oe ped ne 22 vii 5 1 2 Data Arrays a a da a ti E A es ad DEI o A A Pak ewee Sealers eee RUNS 5 27 Manabi Scop aaa Oe bi he A ie oe Bee Ee A 5 3 np t OQutp tin O e arse de ss YG AREAS a ee i 5 3 1 Standard I O with keyboard and monitor 5 3 2 Using Mes TORIO ute ii ato 9A CE UMGRIOR Sie ok ke ee te te a ga a ea to oe ad aaa ae hacen ie he gee Common Gateway Interface 6 1 HTML CGI Program Calling Method Serie arena aoe edo eR BA 62 CGI Program Basic Structures 46 4 se aah oe Bee ee A 6 2 Obtains Im pity A SG Se OW eed O 6 2 2 Processing Detain 9 hah 5 6 Oo he A A te te ed 6 2 3 Output from CGI Application 21 4 ao PS So YES A Writing CGI Programs for Devices 7 1 Step 1 Open a Session with the Device oaoa a a a 7 2 step 2 Getting Data from Input String soi pal a ES eee A 7 3 Step 3 Obtain Device Commands 00 o 7 4 Step 4 Cha
34. ection functions and are explained in full in 19 and user are referred to this manual if more information is desired 15 16 Chapter 4 Remote Access Implementation Method With the advances in modern communication systems the potential to provide remote access to application is becoming easier The Internet has spawned an enormous following and has become a multimedia base communications network Due to the structure of the Internet it is quite reliable and cheap and for these reasons has become an enormous success But because it is a shared media and the number of clients cannot always be known it s performance cannot be measured exactly Taking into mind the Internet s inherent advantages and disadvantages this is the media that was in mind during the creation of this project Nearly everyone can gain access to the Internet from a vast number of locations around the world and due to it s shared nature the cost is relatively low hence making it a perfect resource However the shared nature that makes the Internet so appealing causes a problem security This problem has manifested itself recently as hackers write viruses worms and Trojan horses that gain access to systems thought to be secure causing the need for protection 4 1 Project Background Some of the issues mentioned above are the exact reason that the previous attempts to provide remote access to the ATE racks failed The problem in this case was that the software HP VEE
35. eed to code for error detection and correction is not necessary So for the implementation of web pages for the devices a simple analysis of the feature that the device provides was required Features that only contain a discrete number of setting are more suited for implementation using radio buttons if a continuous number of values where available then a text box should be used The web page created for interaction with the HP 33120A Function Generator is shown in the following figure The function generator s web page above shows how multiple functionality can be implemented on the one page For this web page the selection of the waveform type is done using radio buttons this makes sense as there are only the four different waveforms that the web page will provide The selection of frequency peak to peak voltage and voltage offset is done using text boxes Creating web pages for each device allows the user to access and alter the settings of the specific device that the page was written for But the desire to provide some form of sequencing to the user may be desired This could be done by creating web pages for each step in the sequence then via a navigation frame such as the one used for the main implementation above could be used to step through the steps Providing 92 Figure 8 4 HP 33120A Function Generator Web Page Fla Ca Vaw Favstos EZ Qu ix A G Pra gyre O Sa ds Address B nepuna7 0 0 frames demi A Pari a f Floros 4
36. en when the last receiver releases NRFD and it goes high the interface takes DAV low indicating that valid data is now on the bus In response each receiver takes NRFD low again to indicate it is busy and releases NDAC not data accepted when it has received the data When the last receiver has accepted the data NDAC will go high and the device can set DAV high again to transmit the next byte of data This form of handshaking communication allows the devices to transmit at their own pace and provides error detection through the use if the NDAC not data accepted line If any device fails to perform it s part of the handshaking and releases NRFD or NDAC lines then data cannot be sent this will eventually result in a timeout error 6 2 3 3 Management Bus There are 5 wire allocated to manage the flow of data bytes across the interface and control amongst the various devices connected on the one bus The ATN Attention signal is asserted by the Interface Card to indicate that it is placing an address or control byte on the data bus ATN is released to allow the assigned device to place status or data on the data bus The interface card regains control by reasserting ATN this is normally done synchronously with the handshake to avoid confusion between control and data bytes The EOI End or Identify signal has two uses A device may apply a signal on the EOI line simultaneously with the last byte of data to signal the end of data The int
37. ent services to be provided via plug in This makes the power of HTML almost unlimited 8 1 HTML Basics The HTML language is based on what is known as HTML tags these are used to notify the browser of formatting method The basic structure for all HTML tags are lt HTML_TAG gt to indicate the beginning of an HTML environment and lt HTML_TAG gt to finish the effect of this environment The first tag that must exist is the lt HTML gt tag as it tells the web browser where the HTML code begins and ends This alone would created a valid web page and could be loaded but the result would be a blank screen After the beginning and end of the HTML file is defined there are two more sections that need to be created The first of these sections is the HEAD this section contains information about the web page One such element is the TITLE of the web page the contents of this field will appear in the browsers title bar Additionally the contents of the 45 TITLE field will be used for the history list of the browser and also will be the title entered when the page is book marked The final section that a web page will consist of is the BODY this section contains all the information that is to be displayed on the web page The following code will produce a simple template for a web page lt HTML gt lt HEAD gt lt CENTER gt lt TITLE gt Simple Web Page lt TITLE gt lt CENTER gt lt HEAD gt lt BODY gt lt H1 gt This is a Simp
38. eparated using the amp character so the application must use these special characters to filter out the desired data The post method is much simpler to use as the data is read from the Standard input This is done using the following line bytesRead read STDIN amp readBuf 0 READ_BUFLEN The function requires three arguments then first specifies what input to read from and in this case is STDIN which is defined previously as 0 The second argument is where the data read from the standard in is to be stored the text in this argument specifies the first byte of the bufter readBuf The last argument tells the function the size of the buffer this is so it can keep track of how much more data can be placed in the buffer 6 2 2 Processing Data As mentioned previously the data is sent to the application as one large string this string must first be processed and the different elements separated After the string has been processed and it s elements are obtained and stored in different variable then the appli cation can use the data to perform any task desired In the case of this project after the data has been obtained then it can be used to change the settings on the Automated Test Equipment 36 6 2 3 Output from CGI Application After the application is finished performing all the tasks it is required to then it must respond to the user with some feedback This response must be in the from of a HTML web page and must con
39. er devices such as the Function Generator Oscilloscope and MUX there are far too many options to be included on the one page So some form dividing the these 53 setting must be decided As mention in chapter 7 the device settings are separated into sub command and using these divisions would make sense This type of devision would make the develop ment of CGI programs that are responsible only for a certain sub command decreasing their size and complexity Also be cause the sub division of command is done based on the function they provide this type of division is logical But there is no need to implement all the commands and sub commands as a majority of these features many not be need or could be out of the scope of the users knowledge So providing access to only a small group of commands is also possible and the commands omitted could be left as their default or set to a desire value Creating the web pages in this manner controls the type of settings that the user can use and helps in the coding of corresponding CGI programs The code for the pages created for this project are located in Appendix D these page contain only basic features for each device The other features for the devices can be implemented in a similar manner 54 Chapter 9 Setting Up an Apache Web Server The web server used in the implementation of this system does not matter as long as it is capable of providing the Common Gateway Interface method There
40. eractions The ASCII character set only requires a 7 bit number but most computer systems use 8 bits 1 byte The advantages of using the ASCII character is that the commands can be recognizable to humans and the data can be manipulated quite easily in programming languages The data bus is used to transfer data control information and address An example of how the devices use this is shown using the APPL command used by the Function Generator It contains 5 ASCII characters that can be sent via the data bus one at a time in binary So the decimal equivalent of how this command would be sent is 65 80 80 76 and 58 The devices store the characters in a buffer then apply the command assuming the command is a valid one 2 3 2 Transfer Bus The transfer bus provides a handshaking protocol that allows the system to communicate Asynchronously It does so by allocating each of it s three wire a specific meaning such as Not Ready for Data Not Data Accepted and Data Available Through the use of these control line the system can communication without conflicts and the state of the device can easily be obtain by checking the signals on these wires When a device wishes to transmit data on the bus it sets the DAV line high data not valid and checks to see that the NRFD and NDAC lines are both low and then it puts the data on the data lines When all the devices that can receive the data are ready each releases its NRFD not ready for data line Th
41. erface card can assert EOI along with ATN to initiate a parallel poll Although many devices do not use parallel poll all devices should use EOI to end transfers many currently available devices do not The IFC Interface Clear signal is set high only by the System Controller in or der to initialize all device interfaces to a known state After releasing IFC the System Controller is the Active Controller The REN Remote Enable signal is asserted only by the System Controller Its assertion does not place devices into remote control mode REN only enables a device to go into remote mode when addressed to listen When in remote mode a device will ignore its local front panel controls until the local button is press on that device The SRQ Service Request line is like an interrupt it may be asserted by any device to request the interface card to take some action The interface card must determine which device is signaling SRQ by conducting a serial poll The requesting device releases SRQ when it is polled 2 4 IEEE 488 Connection Details Through the use of the Transfer and Management Bus the IEEE 488 standard is able to have up to 15 devices connected simultaneously with each device being assigned a unique Primary address ranging from 0 30 This is similar to the way that Ethernet works the data is broadcast to all devices and the device uses the addressing information to determine if the data was intended for them A secondary address
42. esis This CD is broken it to the various stages required to implement the remote access that was produced by the project The directories and the files that they contain are 1 Libraries Contains the API library files need to write a program 2 Manuals Contains the various device manuals that contain the commands for each device 3 HTML files Contains the Web pages need to interface with the devices 4 C files Contains the cgi programs source files that interface with the devices 5 Apache Contains the installation executable for the Apache Web Server Chapter 2 IEEE 488 General Purpose Interface Bus The concept of using Automated Test Equipment for automation of test that are mundane and prone to user errors is becoming more of an widely used technique The ability to write a program for a test sequence is becoming more attractive as programs that provide a graphical user interfaces become available These software packages allow the user to interact with the ATE systems via an interface card without having to worry about the underlying system The interface protocol that most ATE systems uses is known as the IEEE 488 standard and has become a solid foundation for future ATE equipment to build on 2 1 History of IEEE 488 Standard The IEEE 488 standard was original started in the late 1960 s as the Hewlett Packard Interface Bus HPIB this was the protocol that Hewlett Packard originally devised to connect and con
43. essed as number of pixels or as a percentage After the frame sizes have been specified the pages that must be loaded into each section must indicated This is the purpose of lines 29 31 and 32 and various options can be applied to each frame such as the no scrolling option that is enabled for the static frame The division of the page and manner in which the pages operate is entirely up to the developer and allows for the implementation of more powerful user friendly sites 51 8 3 Creating HTML pages for ATE Instruments The creation of HTML pages is a creative process and aspects such as appearance and operation can vary tremendously But in the case of web pages for use with programmable instruments there are a few aspects of the implementation that remain constant For example the way that settings are changed is dependent on the way feature being set operates and usually varies from device to device Some setting of a device may be limited to a set of values for example the wave type produced by the function generator so for this reason radio buttons more suit the acquisition of such information It is not totally necessary that the right input type be used but it makes the de velopment of CGI code easier If a text box entry was used to acquire the wave type desired then the CGI application would have to check that the entered wave type is valid and take action if it was not With the use of the best suited input method then the n
44. evice it is talking too As mentioned in the IEEE 488 standard each device is given a unique address see Table 7 1 this address in what is used by the SICL library when communicating with a device Also when the drivers for the GPIB card are setup the interface card is given a unique name so that more one interface card can be in the one system at a time each can be identified by it unique name The way a session is open is similar to the way that C opens a file and is displayed by the following code id iopen hpib7 9 From the line of code above it can be seen that the zopen function is used open a session with a device It only requires the one argument which is a string that identifies the interface card hpib7 and the address of the device on that interface 9 If the function is successful then a variable of type INST will be returned and stored in the id variable and will return 0 if it fails INST is a user defined data type that is de 12 fined by the library This id will be used by the functions that read and write to the devices After a session is created then the printf and ipromptf functions can be used to communicate with the device The strings that these functions use are ASCII characters and are dependent on the device with which the interaction are with The use of these two functions are iprintf id APPL s s n wave_type Vto V_Peek iscanf id t buff iprompt id IDN n t
45. f statements in which the variable is visible If the scope of variables is not considered then this can lead to hard to find bugs A small sample program below displays variable scope RII IA III III IA III IIIS SA III III SIA III IIIS SAS II ISIS SSA II IIA File Name scope c x Description This program demonstrates the scope of X variables in C XK XX Written By Nathan Hetherington hj PAKAKE KAKAK KAAKAA AK KAEKA AKAK KAKAK I ATOR IIA TOSI A ASA A SSS ASI include lt stdio h gt include lt stdlib h gt include lt string h gt int x Defines sub routine void subl void f int x 50 printf x is d in Sub1 n x int main void 27 OMAN DOAK WN HK x 10 printf x is d in the main function n x subl printf x is d after sub1 n x sleep 5000 return 0 The results from running this program after it is compiled results in the following output x is 10 in the main function x is 50 in Subl x is 10 after Subl From examining the output the variable x defined before the main function is seen through out the whole main function the x variable defined in the Sub1 function is only visible to the statements in subl If Subl was meant to change the x variable then this could lead to problems and in a program with more line could be difficult to find This shows that create care with respects to variable scope must be taken when writing C programs 5 3 Input Output in
46. formation technology services due the possible security faults This is understandable as the windows 95 has many security faults and is not recommended as a web server as specified by the apache web server developers So in order to test this system and eliminate any chances of compromising the security of the Universities network the different components that a majority of the Internet used The first element is over an ordinary Ethernet network once success has been proven on this configuration a router will be implemented The router will allow the testing of how the system operates when going from one network to another For the test of the system over an Ethernet the PC s where given IP addresses 192 168 0 1 and 192 168 0 2 respectively The second address was assigned to the PC running the remote access system created by this project Gaining access to the system from the second PC was simple a matter of entering 192 168 0 2 frames html into the address bar of the web browser of the first PC Once performed the introduction web page loaded and the function generators page was chosen Entering data into the fields and pressing the submit button resulted in 63 the desired changes on the instrument then another device was chosen and also proved successful This means that the system operated successfully as predicted under the first test circumstances The next test required the configuration of a router in this case a laptop with
47. gt lt TR gt lt TABLE gt lt BODY gt lt HTML gt This code contain only a small proportion of some of the features provided by the HTML language but the use of options shown in the example demonstrates the convention used for HTML options Line 6 shows how options for the body section can be used to alter the appearance of the overall page the BACKGROUND option allow the back ground of the page to be set to a color or an image the TEXT option defines the fonts color The use of the HR P and BR tags show how they can be used to alter the ap pearance of the page The P tag defines a paragraph and creates the spacing before and after the text that the code encloses The BR tag creates a line break and does not require a lt BR gt tag this is the same as lt HR gt except a horizontal line is created across the page HTML provides the ability to create a list the list will be numbered or have bul let points depending what tag encloses the list In this case the UL tag is used and produces a bullet pointed list if OL was used then the list would be numbered Each element of the list enclosed within the list type are specified by the LI tag The addition of another list type can be used to create a sub list within another list The radio buttons can contain an unlimited amount of elements but only one ele ment can be selected at any time The group is specified using the name field all elements with the same name will bel
48. hat system But a majority of the time the binary version is sufficient and comes in exe or msi format There is not much difference between these two formats except the msi files are smaller The msi windows installer technology contains all data and instructions required to install the application on a system In order to use a msi file then the msi dll dynamic li brary must be installed this is not necessary in later versions of Windows such as XP 2000 For the Windows 95 operating system the winsock libraries have to be updated 56 to winsock 2 before installing the apache server The winsock libraries are what the windows OS uses for network communication and contains functions for the creation destruction and use of TCP communications Web servers use TCP for their communica tions which as stated in 18 1 Accept a TCP connection from client a browser 2 Get the name of the file requested 3 Get the file from disk 4 Return the file to the client 5 Release the TCP connection The file required to add support for msi files and update the winsock libraries are on the attached CD or can be obtained from Microsoft s web site Once the desired version of the Apache web server is acquired then simply exe cuting the exe or msi will initiated the installation process The installation process is pretty much self automated except where information about the Domain and Administrators e mail address are required An
49. ia global environments such as Timeout Whether or not to allow persistent connections and maximum number of requests a server process serves Aspects such as the number of request processed and the timeout are important for this project For the ATE remote access we want only one person changing the device settings at a time using this global variable is not a very effective method of providing mutual exclusion So for future implementation a better method of limiting access to one user at a time would be needed Also the timeout property of the server may need to be changed if the application applying the changes on the device takes to long the a time out may result This could mean that a timeout may result when there is no problems on the server side so increasing this timeout would help prevent this problem But in order to not have the user waiting too long so an approximation of the longest command processing time and a maximum round triptime for the request would need to be estimated The next section of the configuration file deals with the location of various files need by the server including the HTML page that the server will provide access to Along with this it also specifies the that access will be controlled allowing or denying based on user names and passwords or IP addresses This is where security settings can be enforced through the selection of appropriate options 58 Finally this last section allows the establishment of
50. ice a newline character must also be sent to notify the device of the end of the command In the program written for function generator the SIN section of this command string depends on what is selected by the user 41 7 4 Step 4 Changing Settings on the Device Using the command created using the data obtained from the user and the commands for the device demonstrated in the previous step The string can then be sent to the device using the printf function This is done in the following way iprintf id APPL SIN s s s n Frequency PtP Volts Offset This is the line in the code that will actually implements the changes on the device 7 5 Step 5 Error Detection After the string has been sent to the device then it must be checked that the change was actually implemented The easiest way to check that the changes have been implemented is to query the device for it s current setting this can then be compared to the string that was sent to the device The devices current settings can be obtained by using the iprompt function ipromptf id APPL n t temp This will cause the current setting to be in the variable temp as a string this can then be compared using the string compare function strcmp If the two strings are the same then strcpy will return 0 and then the appropriate action can be taken 7 6 Step 6 Output Results Depending on the result of the stremp function a result must be sent to
51. ile in the directory that is password protected this file must be give the name htaccess The fields that must be entered into this file are now describe AuthType Authentication type being used AuthName The authentication realm or name AuthUserFile The location of the password file AuthGroupFile The location of the group file if any Require The requirement s which must be satisfied in order to grant admission The htaccess file created for the project s web server is as follows AuthName ATE User Login AuthType Basic AuthUserFile c Program Files Apache Group Apache2 conf htpasswd AuthGroupFile dev null require valid user From this it can be seen that the basic authentication is used to control the ac cess to the devices this could be and of the various authentication setting depending on the desired effect The path to the password file is specified by the AuthUserFile line and was placed in the conf directory which is only accessible by the web server And the required field specifies that in order to be granted access the user must be have an entry in the password file and the passwords must exist Finally after all files have been created and placed in their correct directories 60 then the httpd configuration file must be edited to inform the server to use password access This is done by editing AllowOverride option of the lt Directory C Program Files Apache Group Apache2 htdocs gt se
52. itten 5 Web pages for interaction with devices had to be written 6 Web server had to be installed and configured At the moment there is no system that provides remote access to the Automated Test Equipment this is due to limitations enforced by the Information Technology Services department of the University The previous system never evolved further then the setup phase before these limitations where put in place for security reasons The software that was going to be used was Hewlett Packard Virtual Engineering Environment Version 5 and was the predecessor of the software being used on the PC connected to the Test equipment Version 5 provided remote access but was hard to configure and required software ports left open listening that are not used by the standard applications permitted by firewalls Along with the inherited security problems that the software processed the Win dows 95 Operating system on which the software ran also created a security threat to the whole University network And to compound the already large deficiencies of the system it s performance was troublesome and unpredictable Hence a need for a method that would remove the security problems and hopefully improve the reliability and performance is the foundation of this project The major proportion of this project is the software generated to provide the re mote access The complete code for this project is contained on the CD ROM attached to the back of the th
53. l of the SICL library is that they are Hewlett Packard dependent meaning that they can only be used in conjunction with Hewlett Packard hardware Although it is limiting the advantage is that the library is efficient reliable and easy to use with HP hardware Also the library can be used to communicate over the different interface methods used for programmable instrument communications such as HPIB GPIB RS 232 and USB This library contains a 32 bit and a 16 bit version for windows which is an advantage as the system connected to the ATE rack is running the Windows c 95 operating system which is a 16 bit OS The SICL library was the only one that worked on the equipment in question for this project so all programs written will use this library 3 1 1 SICL Commands The reader is referred to 14 for a more detailed explanation of the commands and specifics of developing applications using the SICL library But a brief overview of some of the important aspect of the library will be discussed in the following sections The concepts discussed in this section are Instrument independent and will be used for the development on CGI programs in a later section There are a few example programs within 14 so these programs will be referred to rather than new example The first thing that an application has to do before it can interface with a device is create what is known as a device session which creates an ID by which the application can identify the d
54. le Web Page lt H1 gt lt BODY gt lt HTML gt And the resulting web page from the code above is Figure 8 1 Simple HTML page CeO O e Rew REE EI D oe dl ds g This is a Simple Web Page From the simple template this code can be added to to make more complex HTML pages There are heaps of HTML tags that allow the developer to customize the appearance of the web page they are developing Typing text into the body section of the HTML page will result in the text being displayed in the default font and size But tags must be used to format the appearance of the text tables division lines and other elements The HTML language provides the developer with a large range of features just like a word processor to create format documents The developer can insert pic 46 tures table itemized lists and change the appearance of various elements of their page There are such a large number of element that can be changed through the use of HTML tags that readers are referred to introductory HTML books such as 1 or the Internet for various formatting information Another important feature that HTML provide is the ability to create data entry field these are what will be used by this project to pass data to the CGI programs There a few different types of data entry fields but the ones of interest for this project are the text entry field and radio buttons The first element creates a box in which plain te
55. liable code the library provides two functions to add in error detection and correction The first of which is coerror which installs a default error handling routine which is called if any of the SICL functions result in an error The second of which is timeout which allows the programmer to specify a time in milliseconds that SICL will wait for a response from a device When incorporated into applications the programmer can detect errors and take action to minimize or fix 13 such errors 3 2 Virtual Instrument Standard Architecture The VISA library is similar to SICL except they where developed with compatibility in mind allowing the library to be used on any manufactures hardware Agilent Virtual Instrument Software Architecture VISA is an IO library designed according to the VXIplug amp play System Alliance that allows software developed from different vendors to run on the same system as stated in 19 As with SICL the VISA must create a device session before any communications between the interface card and programmable instrument can take place The way that this is done is different then the SICL as two commands are need to create a session These commands are viOpenDefaultRM EdefaultRM viOpen defaultRM GPIBO 22 INSTR VLNULL VLNULL 8vi With the VISA driver a session with the default resource manager must be cre ated before a session with a device This is due to the fact that VISA is an object oriented sy
56. mentation of more functionality for each device Development of a sequence of events for some test Possibly the implementation of a graphical interface using Flash media web pages Implement CGI programs using the VISA API library 66 Bibliography 1 Michael Anderson ATML Complete Sybex San Francisco 1st edition 1999 2 UNKNOWN AUTHOR Danger of Open Port 139 ONLINE 10 11 12 http expertanswercenter techtarget com eac knowledgebaseAnswer 0 295199 sid63_gci980344 00 html ACCESSED 14 10 2004 UNKNOWN AUTHOR The Common Gateway Interface ONLINE http hoohoo ncsa uiuc edu cgi ACCESSED 17 8 2004 UNKNOWN AUTHOR An Introduction to The Common Gateway Interface ON LINE http www utoronto ca webdocs CGI cgil html ACCESSED 18 8 2004 Paul G Green Intelligent HPIB Intrument Control USQ Toowoomba QLD Aus tralia 1st edition 1992 Ron House Beginning with C THOMAS NELSON AUST 2nd edition 1994 Michael I Hyman and Robert Arnson Visual C 5 for Dummies IDG Books Worldwide Inc 919 E Hillsdale Blvd 2nd edition 1997 Agilent Technologies Inc Agilent 33120A Function Arbitrary Waveform Generator Quick Reference Guide 1997 2003 Agilent Technologies Inc Agilent 33120A Function Arbitrary Waveform Generator User s Guide 1997 2003 Agilent Technologies Inc Agilent 349704 Data Acquistion Switch Unit Quick Ref erence Guide 1997 2003 Agilent Technol
57. n the void data type can be used And the user is referred to Appendix C for sample programs 31 32 Chapter 6 Common Gateway Interface The Common Gateway Interface as defined by 3 is a standard for interfacing external applications with information servers such as HTTP or Web servers This allows the user to pass information that can be processed by the application to achieve some goal this type of interface is used for a large variety of tasks These task range from simple applications that query a database or process order information for On line shopping to more complex applications that control equipment such a space telescope or programmable electronic test equipment the reason for this project When using the Common Gateway Interface the web server allows the user to run the application locally on the server This is the most important point the application is not run on the user s system it is run on the system that the web server is installed on So because of this fact the programmer must take some precautions writing CGI programs to ensure the security of the system is preserved As outlined in 3 this security is usually controlled by the administrator of the web server and is performed by controlling the directories that the user can access The CGI applications reside in their own directory this informs the web server to execute these file rather that display them on the browser To ensure a more efficient and comp
58. nging Settings on the Device 0 7 5 Step 5 ao A A ee ey a he ee 107 Step Outp t Results us eta rra lr of peas A 7 7 Compiling Device Programs 2 2 4 20s ara aia a Creating Web Pages for Remote Access Ge HTME Basics tera 24 A Eng Wiel ae ARS ote BA ete oe ir Dies AMS cat oe see eee a a as ate iy as ak aa A a o eat E 8 3 Creating HTML pages for ATE Instruments Setting Up an Apache Web Server 9 1 stalline Apache o ae Fe Gs a laa BA e a ni 33 34 34 35 36 37 39 39 40 40 42 42 42 43 45 45 49 52 55 9 2 General Configuration 4 a a ee ee 58 A O ula o A de ie es ace oh be ae at ace ee SS eee 59 9 3 1 Controlling Access ae ate a a e a Bh os 59 9 4 Adding Web Pages and CGI Programs 0004 61 10 System Test 63 11 Conclusion 65 11 1 Suggested Further Development ais wre ot ba ane oi bee A 65 A Project Specification 69 B ASCII Character Set 71 C GPIB Interface Cards 73 D HTML Pages 85 D 1 Function Generator 2 A A A A NO leia 85 D2 oc Un is o A A a male ee ia 86 LES Power Suppl boe Ys fy te oe a ee 4 oh a E ee E 87 IDA Asclostope s Lala Perard on pts eke rd ome ee OA 88 E CGI Applications 91 E 1 Basic CGI Applications 2c o 9 hawt E Ee 2 ES 91 E 1 1 CGI get Method e A A A ge ee 91 ELO CGL peste Mend s e d ea ER ae ee de 97 E 2 CGI Programs for Devices 3 us ue edag tele Yookn ig Geeks Wok ot Se 100 E 2 1 Function Generator ss ka oS ee
59. ntains the path of the application and is referenced from the web servers main directory There are no limitations on the number of forms displayed on the one web page so it is possible to have multiple submit buttons corresponding to separate applications Caution must be taken when using multiple forms to ensure the correct application is called for each data set 6 2 CGI Program Basic Structure The basic operation of the CGI is shown in the following picture obtained form 4 From this figure it can be see that is the Common Gateway interface is comprise of the three components mentioned in Chapter 4 This section will deal with the creation of the Gateway programs depicted in the diagram All CGI applications will follow the same basic structure and are comprised of three sections These are obtaining input from the user performing applications task and outputting a web page to user containing the status of the application The reader is referred to Appendix E 1 which contains CGI example programs obtained from 13 34 Figure 6 1 Flow of data to a gateway application HTTP SERVER Y gateway programs 1 CLIENT Web browser 6 2 1 Obtaining Input The main purpose of a CGI program is to obtain information from a web page then use this information to carry out some tasks There are two way that a CGI program can obtain data from a web page and these are 1 GET the data are passed within the query string of the
60. ogies Inc Agilent 34970A Data Acquistion Switch Unit User s Guide 1997 2003 Richard Johnsonbaugh amp Martin Kalin Object Oriented Programming in C Pren tice Hall Upper Saddle River New Jersey 2nd edition 2000 67 13 14 15 16 17 18 19 John Leis HTML Forms and CGI ONLINE http www usq edu au users leis notes html index html ACCESSED 4 6 2004 Hewlett Packard HP Standard Instrument Control Library User s Guide for Win dows 3rd edition 1996 John M Pieper Automatic Measurement Control Rohde amp Schwarz GmbH amp Co KG Muhldorfstrabe 15 81671 Munchen Germany 1st edition 2003 Robert W Sebesta Concepts of Programming Languages Addison Wesley 75 Ail ington Street Suite 300 Boston MA 5th edition 2002 STROUSTRUP C PROGRAMMING LANGUAGE ADDISON WESLEY 3rd edition 2000 Andrew S Tanenbaum Computer Networks Pearson Education Inc Upper Saddle River New Jersey 07458 4th edition 2003 Agilent Technologies Agilent VISA User s Guide 5th edition 2001 68
61. ong to a group The value field is used to separate each of the elements of a group this is so that the individual button can be identified One final feature of the radio button is the ability to specify a default value this is so that one of the group is always selected and is done using the checked option Finally is the text entry field this element allows the user to under strings that can be used by a CGI program This element is created using the input tag the type of input is specified using the type field and the size option specifies the number of characters that can fit in text field Just like the radio buttons the text field has it s own unique 48 29 30 31 32 33 34 35 36 37 38 39 40 41 name specified in the name field The way that the text fields are displayed in the above example uses a table structure which allows the creation of a matrix with the text fields as the elements This structure is simple to create with the PR tag used to create a matrix row and the TD tags create columns This allow the developer to group similar fields to create some logical grouping of data The figure below shows the page resulting from the code Figure 8 2 Web page with Background and other elements jaion Bookmarks Mail Window Help tt baun PS EN BUY OPERA TODAY lt E And make this banner go away 8 2 Frames Also HTML allows the developer to create what are called frames which allows
62. pages with their corresponding CGI program Each page would handle one or more of the steps for the sequence The actual way that this is implemented is entirely up to the programmer and due to the modular structure the separate components could be used separately or in various sequences 20 Chapter 5 Writing C Programs The first and often most important decision when undertaking a software development project is what programming language to use Some of the criteria that must be considered as outline in 16 these are Readability Writability Reliability and Cost Each criteria must be considered in great detail as their weighting will vary for differ ent projects for example a real time system will place greater importance in the reliability Also in conjunction with these criteria other factors can greatly influence the de cision of what programming language to use In the case of this project the availability of the Application Programmers Interface for a programming language played a major roll The API for the GPIB interface card was only available for C C and Visual Basic so a decision between the two had to be made Visual Basic is a simple programming language that allow the user to write pro grams quick and easily But as with nearly everything this advantage comes with a cost visual basic programs can be unreliable and can be limiting in what features are provide for the programmer to use The C C programming lang
63. ss then that of the par allel systems this is due to the fact that they can only send 1 bit at a time But the distances that a serial communication link can send is usually larger and the error recovery is easier as the use of a parity bit is often sufficient to correct errors In parallel communication if an error occurs then more then one bit may be corrupted and retransmit is required The type of communication link required depends on environment under which the equipment will be used but the advantages of the 24 wire connection make it the dominant method used 2 3 IEEE 488 Connector and Wire Configuration The type of connectors and wiring depends upon the type of interface card that is chosen to interface with the devices In this section the original 24 wire cable and connector will be considered The cable and connectors often refereed to as the CN24 connector due to the fact that they are comprised of 24 connector pins and 24 wires the picture below depicts such cables and connectors Figure 2 1 IEEE 488 CN24 cable and connectors Back As mention the cable that is usually used for GPIB interactions is a 24 wire cable of which 8 of these wires are used for ground The remaining 16 wires are then broken into three groups 1 Data Bus 2 Transfer Bus 3 Management Bus 2 3 1 Data Bus The data bus occupies 8 of the 16 signal wires this is due to the fact that most of the devices use the ASCII character set for there int
64. stem and the word resource more specifically refers to a particular implementation or instance in object oriented terms of a Resource Class The resource manager is what maintains all of the class instances so the class that is about to be create must be registered with it This class is then linked to the device this section is similar to SICL The interface card is identity and the address of the device are specified via a string The next two arguments are VILNULL which means Do not return the number of bytes transferred these are constants defined in the VISA library which alter the operation of the VISA functions Finally the last argument is the address of a session variable and is exactly the same as the ID variable in the SICL library it is used by the I O functions to determine what devices they are talking too The Input and output functions of the VISA library works exactly the same as in SICL These functions are viPrintf and viScanf and their arguments are exactly the same as the previously explained printf and iscanf each requiring a session id a string and the name of any variables that are being used in the string The following shows their operation viPrintf vi IDN n viScanf vi t buf 14 Closing the session after all the interactions have taken place is performed via the viClose command with the session id being passed to it as it s argument The VISA library has a large range of error det
65. system to fail 64 Chapter 11 Conclusion At the completion of the thesis the system provides a small amount of functionality for each device and web pages through which the interactions are performed An Apache web server that hosted these web pages and provided password controlled access was installed and configured This was the major achievements of the project The web pages created to provide remote access to the devices could be used to provide access to the ATE Rack for external students This would benefit student that would normally have to travel long distances to access these devices Also assignments and practical assessments could be created using web pages and CGI programs for students to complete remotely Also it is suggested that the systems that the ATE equipment is attached to is updated with more powerful computers This will improve the security and performance of both the existing system and the system produced by this project It will also help improve the development and testing of software developed using the methods outlined in the thesis The initial direction of this project was not as the author expect with a client server software development The development of a web based system was emphasized by the Supervisor as it solves some of the existing problems so this was fully developed 11 1 Suggested Further Development Improvements to the current remote access system could include 65 The imple
66. tain all the headers and trailers that a standard web page contains This can be seen in the examples in Appendix E 1 1 with lines 51 to 62 of cgiget c defining the HTML header and 262 to 264 adding the HTML trailer Any code can be entered between the header and trailer as long as the code fol lows the HTML format The programmer can use any functions from the string h library to manipulate the strings that will be displayed on the web page and all information will be in the form of ASCII characters Because the program is what is responsible for the reply then the information that is sent back can depend on the results of the processing making the application capable of dynamic web development The sending of data back to the user is performed using the printf within C which prints to the standard output 37 38 Chapter 7 Writing CGI Programs for Devices The programs that are written for interacting with the devices of the ATE will follow the structure outlined in the previous chapter on Common Gateway Interface The cgi program written for the Function generator will be the eample referred to in this chapter while describing the process involved in the creation of these programs The process described for this application is exactly the same for each device with little variation so can be used to create programs for the different programmable instruments available 7 1 Step 1 Open a Session with the Device In order to communi
67. trol devices that they manufactured With the introduction of programmable devices the need arose for the introduction of a standard by which devices from different manufactures could interfaced was required In 1975 the Institute of Electrical and Electronic Engineers IEEE published the IEEE 488 standard that detailed the electrical mechanical and functional specifications of the interface bus This interface bus was specifically designed for the interaction with programmable instrumentation and was reviewed in 1978 but no major changes where made to the standard This standard is now in world wide use by the major programmable instrumentation manufactures and known by three different names 3 1 Hewlett Packard Interface Bus HPIB 2 General Purpose Interface Bus GPIB 3 IEEE 488 Bus Work on standard continued as the original standard did not outline the syntax and formating conventions for the communications with devices Finally the new standard was completed and released as the IEEE 488 2 with the original standard being dubbed IEEE 488 1 This standard contained information on Codes Formats Protocols and Common Commands for use with the IEEE 488 standard The new standard did not replace the original with most new devices supporting both instead it provides a reasonable level of compatibility Finally in 1990 the IEEE 488 standard was appended to include the Standard Commands for Programmable Instrumentation SCPI documents
68. tten to perform reliably no matter what the size of the data types especially when the program is obtaining memory dynamically An example program is shown in Appendix C it shows how to define various data types and the use of the sizeof function The final data type that C provide is the pointer this data type is used to store memory addresses This data type allows C programs with a very powerful tool as it 24 allows for functions to access variable outside their scope and the allocation on dynamic variables With the use of pointer the programmer is able to create abstract data types that can grow in size dynamically which useful when the number of elements is unknown The basic way to define a pointer is by putting a character directly in front of the variable name The pointer can be of various data types so that the compile will know how many bytes there are to each variable This is required for features such as the increment and decrement functions provided by C on pointers The creation of a C pointer is demonstrated in the following code int int_ptr int_ptr malloc 5 sizeof int The first line of code creates a pointer to a int type variable at this stage the pointer is full of random garbage which happens to occupy the memory location assigned to it by the compiler The second line user the malloc function to create a block of memory with 5 integer sized variables note that the 5 could easily be a variable with any val
69. uage on the other hand is one with a much longer history and although it is a high level language it also provides low level features that the programmer can implement into there code C C are languages that are very powerful and provide the programmer with a large array of features but can be dangerous if used incorrectly by the programmer Although I have had experience with both of these languages the C C pro gramming language is the one that was chosen for this project This is due to the fact that I have had more experience with the language and the programs compiled in C C 21 are more efficient eg Run faster more reliable than most other languages In addition the advantage of object oriented programming provided by C allows for more efficient code to be produced if desired The reader is referred to suitable introductory books if the fundamentals of C C are not known Suitable books include Beginning with C by Ron House 6 and Object Oriented Programming in C by Richard Johnsonbaugh and Martin Kalin 12 however the some of the basics will be outlined in the following chapter 5 1 Data Types and Structures The most important structure in any programming language is the variables in which data can be stored manipulated and retrieved The C C language has a vast variety of data types that the user can user and structures that allows the user to group variables that logically belong in one structure 5
70. ue If the malloc function is successful in the creation of this memory block then the address of the first byte of the block is returned and entered into the int_ptr variable however if malloc fails NULL is returned The most important thing to note here is that the variable int ptr contains the address of the variable hence to access the contents of the memory address the indirection operator must be used This must be placed before the variable name similar to the way the pointer is created then the pointer can be used just like a normal variable This property will be shown in the following example int pir 4 printf The pointer contains d A 5 1 2 Data Arrays The previous data types are only capable of holding one variable at a time In most cases such as a string of characters are need especially when writing programs for the GPIB as the commands to the devices are comprised of string of ASCII characters So a way in which logically grouped data can be stored is required 25 The C C languages provide the user with the ability to define an array of a specific data type of any dimension The way in which an array is created and indexed is as follows char array 10 int intarray 10 10 array 0 h intarray 0 0 2 With indexing an array in C the index range is from O to the size 1 so in the example above the index is 0 to 9 The second line in the example shows how a multi dimensional array is
71. virtual hosts which allows multiple domain hostnames to exist on the one server This maybe desirable if the server is to host web pages for different sites such as a web hosting service would provide In the case of this project there is no need to have multiple domains or hostnames so this section will be left as is As mentioned earlier there are many sources of apache web server configuration on the Internet Hence the user is advised to search on the Internet for help regarding to the configuration of Apache Web Servers if more detail is required The site from which the Apache server is obtained www apache org is recommended as a good starting point for such information 9 3 Configuring Server After the web server is installed then all configurations are done via the httpd configu ration file This file is accessed and edited using a simple text editor and contains code that look similar to HTML code This file is read by the server application upon starting and specifies the operation of certain aspects of the server 9 3 1 Controlling Access For this project there is the desire to provide a form of controlling access to this web site Through the use of the httpd configuration file files created by the administrator and a file created by an application provide by the apache server this facility can be provided The first stage in configuring controlled access is the creation of a password file this is done using a program
72. ww whatis com 2004 is the specific method prescribed by a computer operating system or by an application program by which a programmer writing an application program can make requests of the operating system or another application In the case of this project the desired API is for the GPIB card so that programs can be written to interface with the programmable instruments via the GPIB interface card After some researching on the topic of an API for the GPIB interface card con tained in the system that the remote access is to be implemented the manufactures of the card Agilent Technologies Inc provide the API for download as part of a drivers suit Contained with the drivers which are necessary for correct operation of the card are two API s Which where the Standard Instrument Control Libraries and the Virtual Instrument Standard Architecture and these will be discussed further in the following sections 3 1 Standard Instrument Control Library The Standard Instrument Control Library is a modular instrument communications library that works with a variety of computer architectures I O interfaces and operating systems according to 14 This Library allows programs to be written in C C or Visual Basic that can interface with a GPIB card One of the advantages as stated in 14 is that programs written using this library can be ported at the source code level from one system to another without or with very few changes 11 One down fal
73. xt can enter the maximum size of which can be set The next has a grouped set of options of which only one can be selected at any time The tags just mentioned will be displayed by the following code and explained af ter the code lt This creates a comment gt lt HTML gt lt HEAD gt lt TITLE gt Customized Web Page lt TITLE gt lt HEAD gt lt BODY BACKGROUND background jpg TEXT FFFFFF gt lt CENTER gt lt H1 gt This is a Simple Web Page lt H1 gt lt CENTER gt lt P gt This is an Itemized List lt P gt lt HR gt lt UL gt lt LID gt Item 1 lt LI gt lt LI gt Item 2 lt UL gt lt LI gt Item 2A lt LI gt lt LI gt Item 2B lt LI gt lt UL gt lt LI gt lt LI gt Item 3 lt LI gt lt LI gt Item 4 lt LI gt lt UL gt lt HR gt lt P gt Radio Buttons lt P gt lt input type radio name group1 value Button1 checked gt Button 1 lt br gt lt input type radio name group1 value Button2 gt Button 2 lt br gt lt input type radio name group1 value Button3 gt Button 3 lt br gt lt input type radio name group1 value Button4 gt Button 4 lt br gt lt HR gt 47 Oo oN DTA RAUNA lt TABLE align center border 3 width 668 cellpadding 3 id table1 gt lt TR gt lt TD width 222 gt Text 1 lt input type text name text1 size 20 gt lt TD gt lt TD width 222 gt Text 2 lt input type text name text2 size 20 gt lt TD

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