The NetPorter DAQ is especially well-suited to work with NetPorter software. Let's look at a simple example that has the board controlling a Web page. The NetPorterDAQ has 5 analog inputs, but the page only shows the first one. The Web page does some numeric processing using JavaScript and also shows LEDs for digital input:

You can download the files that make up this example.

Here is the important part of the properties file:

defaultuser=xlw
defaultpassword=bnetpdemo
defaulthost=netporter.al-williams.com
defaultdirectory=c:/user/awce/netporter/daq/files
defaultftpdir=public_html
defaulttemplatedir=c:/user/awce/netporter/daq/templates
smtp=smtp.al-williams.com
fromaddress=netporter@al-williams.com
rules=c:/user/awce/netporter/daq/rules.txt
stimulus=c:/user/awce/NetPorter/daq/stim.txt
port=COM1
baudrate=19200
bits=8
stopbits=1
parity=0
flow=1

This is pretty standard. Just 19,200 baud on COM 1 with RTS/CTS handshaking. The stim file, is empty and just a place holder, by the way.

The rules.txt file looks like this:

MATCH (.+)=(.+)
SET $1=$2
BUILD daq.template
SAVE daq.htm

That's it. NetPorter DAQ is set to output data periodically and the format is exactly what NetPorter wants.

Now the template that forms the Web page:

<HTML>
<HEAD><TITLE>Netporter Data Acquisition</TITLE>
<META HTTP-EQUIV=REFRESH CONTENT=15>
<SCRIPT>
<!--
function convert(ct)  // function converts raw counts to voltage
{
  var v;
  v=ct*5/1023;
// round to 2 places
  v=Math.floor((v+.005)*100)/100
  return v;
}
//-->
</SCRIPT>
</HEAD>
<BODY BGCOLOR=cornsilk>
<h1>Analog Data</h1>
Voltage on A0=
<SCRIPT>
<!--
document.write(convert(<VAR A0>));  // note NETPORTER variable
// of course you could loop and do them all :-)
//-->
</SCRIPT>
 Volts (RAW = <VAR A0>) <!-- another NETPORTER variable -->
<HR>
<H1>Digital Inputs</h1>
<TABLE BORDER=0 BGCOLOR=#F5E5E8>
<TR>
<SCRIPT>
<!--
 byte=<VAR D0>;  // Read the NETPORTER input

// this loop picks a lit or dark LED for each bit
 for (mask=0x80;mask!=0;mask=mask>>1)
  {
  if ((byte & mask)==0) led="ledoff.gif"; else led="ledon.gif";
  document.write("<TD><IMG SRC='" + led + "'></TD>");
  }
//-->
</SCRIPT>
</TR></TABLE>
</BODY>
</HTML>

That's it! You can view the page at your server address port 808 (unless you changed the properties file to use another value). So on your local machine, you'd view http://localhost:808/daq.htm, for example.

A few important notes:

  • The page refreshes every 15 seconds thanks to the META tag near the top of the file.
  • There are two spots where NetPorter writes a variable inside JavaScript. This allows you to send NetPorter variables to JavaScript routines. Document.write allows JavaScript to send data to the user's browser screen.
  • The raw count is also shown using a NetPorter variable, but this time in normal HTML
  • ,

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