Remote Instrument Control Through Internet

Gu Feng

July, 1998

Content

• Introduction

• Development of RICI using CGI

• Development of RICI using Java

• Conclusion

• Future Work

Introduction

• Possibility of RICI

• Unified user interface

• Ease of usage

• Interactivity

• Benefit

Introduction

• System Structure

Development of RICI using CGI

• CGI is an acronym for the Common Gateway Interface, which defines the standard way in which external programs should communicate with a Web server.

• Typical procedure of controlling a remote instrument

– Using any internet browser to connect to the web site where the instrument is located.

– The web server will provide a web page, which enables users to enter desired instrument parameters and submit them to the web server.

Development of RICI using CGI

– The CGI program on the web server will determine whether

the entered parameters are acceptable or not.

– If the entered parameters are acceptable, the CGI program

will generate commands and transfer the commands to the

Lab PC to which the instrument is connected and controlled.

– The Lab PC will execute the commands and acquire output

of the instrument.

Development of RICI using CGI

– The acquired data will be transferred from the Lab PC to the

CGI program.

– The CGI program will then translate the acquired data to

HTML format and send them to the remote user.

Development of RICI using CGI

• What is Virtual Instrument?

AD/DA CardGPIB Card, etc.

Software

Virtual Instrument

Development of RICI using CGI

• Virtual Instrument - Sine wave signal generator

Development of RICI using CGI

• Start page • Result page

• Demonstration

Development of RICI using Java

• Java– platform independent– compile once, run anywhere– java applet can run on client side– more flexibility, interactivity and immediacy– continuous connection between client and server– more friendly and easy-to-use user interface

• Typical procedure of controlling a remote instrument

– Using any internet browser to connect to the web site where

the instrument is located.

– The web browser will automatically download a java applet

and run it.

– The Java applet will establish a TCP connection with the

server program running on web server.

Development of RICI using Java

Development of RICI using Java

– The user will enter desired parameters and click <run> button.

– The java applet will send the parameters to the server program.

– The server program will determine whether the entered parameters are

acceptable or not.

– If the entered parameters are acceptable, the server program will

generate commands and transfer the commands to the Lab PC to which

the instrument is connected and controlled.

Development of RICI using Java

– The Lab PC will execute the commands and acquire output

of the instrument.

– The acquired data will be transferred from the Lab PC to the

server program.

– The server program will then generate a GIF file according

to the acquired data and inform the java applet that the GIF

file is ready.

Development of RICI using Java

– The Java applet will fetch the GIF file and display it on the user’s screen.

– To get a new result, the user just need to change the value of parameters and click <run> button.

Development of RICI using Java

Demonstration - Start page

Development of RICI using Java

Demonstration - Result page

ConclusionDifference between CGI method and Java method

Item CGI method Java methodProgramminglanguage

any language: C, Perl, Tcl/Tk,shell script

Client side: java ;Server side: anylanguage

platform dependent yes noexecution server client and serverexecution speed fast faster

Conclusion

Item CGI method Java methodhardware requirementof client PC

no must be powerful enough torun java applet

software requirementof client PC

graphical webbrowser

graphical web browser withJava support

connection per session basis continuous

user interface friendly friendly and flexible

Difference between CGI method and Java method

Conclusion

Item CGI method Java methodapplication for using instrument with few

parameter and infrequentlyadjustment only, i.e., voltagemeasurement.Not applicable for PID tuning

any instrument

compatibility any web browser, even lynx not good, alwaysneed latest graphicalweb browser

Future Work

• authentication

• encryption of transmission

• integration with Computer Supported Cooperative Work

• potential application in industry