VIRTUAL REMOTE MEASUREMENT OF CONTROLLED SOURCES

Authors:

Florin SANDU, Gheorghe SCUTARU,

Ioan Emilian CUCERZAN, Daniel IOLU

Application Idea

„Leonardo da Vinci” Pilot Program RO/01/B/F/PP141024 “Virtual Electro-Lab”

The main goal of the program is the Internet publication not only of information but also of experimental resources

A client – server application to ensure remote and virtual measurement

Application Structure Client

Web Browser Html pages and Flash movies for stimuli submission and

results display

Server Web Server

PHP used to pass stimuli from the client to the server Workbench Server

LabView used to process stimuli, to perform the measurement and to create different formats of results

PSpice used for circuit simulation

Application Architecture

Client Web Server

Workbench Server

Internet

LAN

IBM PC Web browser Flash 5 plug-in

ACPI Multiprocessor PC MS Windows 2000 IIS Server PHP 4

Pentium PC with AT MIO 16E10 acquisition board

MS Windows 2000 LabView PSpice

WEB Application Interface

“hyper-schematic” where the user can directly change parameters

the node voltages (the student can notice the correct Bias-Point of the BJT)

factor divider current of inverse

3R

3R2R1R

1RI AC

1G inV c

I AC

plot of the

Application’s VI

First frame of the VI, containing a wait – loop

Application’s VI

Variables' extraction from the stimuli file and

construct of the “.cir” file

Application’s VI

Frame for the “System-Exec” sub-VI

Application’s VI

Frame 4 of the VI, containing the construction of the“op3_val.txt” file, the graphics arrays construction and the copy of op3.out from the work-bench to server

Application’s VI

Graphics plot and image-to-file save frame

Flash 5 advantages

Vector graphics Easy to use editing environment Scripting language(“ActionScript”)

Movie control gotoAndPlay gotoAndStop stop

Communication capabilities LoadVariablesNum GetURL

The structure of our interface

1 scene

3 layers

4 frames

PHP structure <?php

//gets all variables from swf file

$r2 = $HTTP_POST_VARS['r2'];

$r3 = $HTTP_POST_VARS['r3'];

$r4 = $HTTP_POST_VARS['r4'];

$r5 = $HTTP_POST_VARS['r5'];

$r6 = $HTTP_POST_VARS['r6'];

$c1 = $HTTP_POST_VARS['c1'];

$c2 = $HTTP_POST_VARS['c2'];

$c3 = $HTTP_POST_VARS['c3'];

$v2 = $HTTP_POST_VARS['v2'];

//create and open the output file

$filename="./values.txt";

if (!file_exists($filename)) {

touch($filename); // Create blank file

chmod($filename,0666);

}

$f=fopen($filename,"w");

//writes the input values in file "values.txt"

fputs($f,"R2:".$r2."\n");

fputs($f,"R3:".$r3."\n");

fputs($f,"R4:".$r4."\n");

fputs($f,"R5:".$r5."\n");

fputs($f,"R6:".$r6."\n");

fputs($f,"C1:".$c1."\n");

fputs($f,"C2:".$c2."\n");

fputs($f,"C3:".$c3."\n");

fputs($f,"V2:".$v2."\n");

fclose($f);

?>

Practical student works

The display of node voltages

Practical student works

The gain plot

Practical student works

Cuasi-open loop gain as reference for auxiliary graphical construction

VCCS Application Interface

Text boxes for numerical submission (with default values)

VCCS Application Interface

IC vs frequency simulated characteristic

CCCS Application Interface

Text boxes for numerical submission (with default values)

CCCS Application Interface

The display of node voltages

CCCS Application Interface

IC vs frequency simulated characteristic

CCVS Application Interface

The display of node voltages

CCVS Application Interface

Gain vs. frequency simulated characteristic

Conclusions

The integrated LabView work-bench server provides robust equipment control and direct Intranet communication with the server

The “wysiwyg” remote testing, combined with complete PSpice simulation and theoretical computation has a great educational impact

The results can be extended to electro-mechanical automation & robotics, with an implementation that should also include virtual reality