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Suppose that you had an instrument that can be controlled
by sending commands to it via a serial port, but you need
to be able to control that device from anywhere in the world
through the internet simply by using an HTML form. The technique
outlined below makes this possible and if you use it in conjunction
with the Wedge2URL program you can
even display any data that is returned by the device on the
same web page.
Unfortunately Active Server Pages do not support Dynamic
Data Exchange, so we cannot simply add DDE Commands to our
VBScript. Instead we will use a compiled Visual Basic Program
and call it from our ASP code with the data to be transmitted.
- Download and
install the Project files.
- Copy the ASP files onto your Web Server.
- Set up WinWedge.
- Change the Com port information in the Setup.ini file.
- Launch WinWedge (Activated) on the PC that has the Serial
Device connected to it (This must be the web server*).
- Open Multi_Field.asp through HTTP in your web browser
from any PC that has access to it.
- Type in the data to be sent out the serial port and click
on send.
- If everything works as it should then the device will
receive the command and respond appropriately. If this
does not happen check the troubleshooting section
of this page.
* You could attach the serial device to any PC on your network
and use TCP/Com to
share the serial port as a TCP/IP Port, then run TCPWedge on
the web server instead of WinWedge. Minor changes to the
VB Program would be required - the DDE Application Name and
Topic would need to be changed to work with TCPWedge instead
of WinWedge.
- PC running Microsoft Windows 9x/NT4/2000/XP.
- ASP compatible Webserver e.g, Personal WebServer 4.0
or IIS 4.0 or later.
- An available RS-232 Serial Port.
- WinWedge v1.2 or later from TALtech, Inc.
- Compatible RS-232 Serial device.
- Microsoft Visual Basic 6.0 or later (to view, modify
and recompile project files)
- Internet Explorer 4.0 or later (recommended) or other
Windows compatible Web Browser.
- TCPWedge (optional) and FREE with WinWedge Pro.
- TCP/Com (optional) and FREE with WinWedge Pro.
When the user opens the ASP page in their browser there
is a text box (part of an HTML form) that allows you to enter
the command to be sent to the device. Commands should be
entered in the format:
Where x represents an ASCII control character such as ESC
(ASCII 27) or Carriage Return (ASCII 13). for Example, you
may need to send ESC P to a device asking it to print the
current reading. You would use:
If you needed to send S<CR><LF> you would use:
When the form is submitted, the specified command is passed
on the command line to the Visual basic program (ASPSendOut).
ASPSendOut establishes a DDE Link to WinWedge and uses the
'SendOut' DDE Command to pass that command to WinWedge. WinWedge
sends the command out the serial port to the device. Assuming
you are also running Wedge2URL then any returning data will
be displayed in the web browser along with the form again
which gives you the opportunity to send the next command
to your device.
Simply configure WinWedge to work with your device (Follow
the Quick Set Up Steps at the front of your WinWedge Manual).
Don't worry about trying to parse and filter your data, this
will be done in the ASP code.
Note: Because WinWedge always behaves as a DDE Server regardless
of which mode you choose, you can use the example below in
Keystrokes mode, DDE Mode or Log to disk mode (Pro version
only). This means that not only can you update your ASP Page
but at the same time you can record your data in Excel, or
notepad, or a log file!
The format described here is an implementation of the ".INI
File Format", as defined in the Microsoft Windows for
Workgroups Resource Kit. An INI file is a text file divided
into sections, each containing zero or more keys. Each key
contains zero or more values.
Example:
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[SectionName]
keyname=value
;comment
keyname=value,
value, value ;comment
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Section names are enclosed in square brackets, and must
begin at the beginning of a line. Section and key names are
case-insensitive, and cannot contain spacing characters.
The key name is followed by an equal sign ("="),
optionally surrounded by spacing characters, which are ignored.
If the same section appears more than once in the same file,
or if the same key appears more than once in the same section,
then the last occurrence prevails. Multiple values for a
key are separated by a comma followed by at least one spacing
character.
The Setup.ini file for ASPSendOut looks like:
You can also use the same Setup.ini file as ASPSendOut Program.
The code for the visual basic program is based on the WinWedge
DDE Example for Visual Basic - Sending
DDE Commands To WinWedge From A VB Application. At its
most basic, the Project consists of a only a single form
and a module but, to make our example more useful, instead
of 'hard coding' variables like the selected com port we
added code to read these parameters from a setup.ini file.
This method allows you to easily add more of your own settings
and change variables without needing to recompile the program
each time.
There is no need to display a screen shot of the form as
it is never displayed on screen. Instead all we run is the
Main Subroutine.
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Sub Main()
'checks for command line
arguments, if found it will send the passed
' value out the serial port, if not an error message is displayed
'Declare Variables
Dim str2Send As String
'Get
data inputted on the command line
str2Send
= Command$
If Len(str2Send) Then
' by referencing the form an instace of it
is created in memory (though not
' on screen, the onload event of the form will fire and the DDE Link
to WinWedge
' Will be opened and data transferred
Form1.Text1.Text = str2Send
Unload Form1
Else
MsgBox "No command specified:" & vbCrLf & "e.g.
ASPSendOut 'Print',13", vbExclamation + vbOKOnly, "Error"
End If
End Sub
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The ASP Code below is a modification of that used with Wedge2URL.
Not only will it display wedge data submitted from Winwedge
but it also displays an HTML Form that allows you to enter
data to send to WinWedge through ASPSendOut. The New Code
is presented in bold Text. It requires you to Have
the Windows
Script Host installed on the web server.
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<% @Language
= VBScript %>
<%
'declare variables
Dim strWedgeData, WshShell, str2Send
Dim StartPos, MyVar, DelimPos
Dim Myarray(3) 'Specify the number of fields you defined in WinWedge between
the parenthesis
'retrieve
wedgedata information
strWedgeData = Trim(Request.QueryString("WedgeData"))
'retrieve
data to send out the serial port, if any
str2Send = Trim(Request.QueryString("strToSend"))
'How
to separate multiple comma delimited fields from
the single strWedgeData variable:
'Add
Terminating comma
MyVar = strWedgeData & ","
'
starting position in the string - start at 1st
byte
StartPos = 1
'
scan until we reach the end of the string
While StartPos < Len(MyVar)
'
find the next comma delimiter
DelimPos = InStr(StartPos, MyVar, ",")
'
pull out a data point between the starting position
and the position of the delimiter
DataPoint = Mid(MyVar, StartPos, DelimPos - StartPos)
'
update the starting position (skip over the delimiter)
StartPos = DelimPos + 1
'
Field counter
fCount = fCount + 1
'
save the current data point
Myarray(fCount) = DataPoint
' go get the next data point
Wend
'set
default values
if str2Send = "" then str2Send = "'test',13"
if str2send = "" then strWedgeData = "No Data available at this
time"
'run
ASPSendOut
set WshShell = CreateObject("WScript.Shell")
WshShell.Run("c:\ASPSendOut.exe " & str2Send)
set WshShell = nothing
%>
<HTML><BODY><H1>Current
Wedge Data:</H1>
<%
Dim i
'Loop through
each record in the array and display the data
For i = 1 to Ubound(Myarray)
Response.Write("Field " & i & " = " & Myarray(i) & "<br>")
next 'i
%>
<form
Action="<%= Request.ServerVariables("SCRIPT_NAME")
%>" method="GET">
<Input name="strToSend" value="<%= str2Send %>"> String
to Send out the Serial Port <BR>
<Input type="Submit" name="Submit" Value="Send"></form>
</BODY></HTML>
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Nothing happens!
- Is WinWedge Activated and set up correctly for your device
on the right com port?
- Did you upload the ASP files to your wbserver?
- Did you specify a valid Command for your device?
- Try troubleshooting by Activating WinWedge in Virtual Instrument mode: any
data submitted for sending out the serial port should appear in the WinWedge
Window. Verify that it does and that the command appears correctly.
- Is the Windows Script Host installed.
- Did you modify the code to point to YOUR file locations?
- Did you setup permissions on your webserver for running executables?
- Did you modify the Setup.ini file to point to your com port?
- Can you get the code to run Notepad instead of ASPSendout?
Unfortunately this is not the sort of application that is
likely to run "right out of the box" and a lot
of tweaking may be required. If you cannot make it run after
trying all of the above, then you may be able to use PERL
instead of ASP. A similar program for Perl can be found here that
would not take long to adapt for this application.
ASPSendout doesn't run!
This program requires the Visual Basic Runtimes. Download
them Now:
 Vbrun60.exe (size:
1.34MB)
Reference :
For additional information, please see the following article in the Microsoft
Knowledge Base:
ARTICLE-ID : Q192461
TITLE : FILE: VBRUN60.EXE Installs
Visual Basic 6.0 Run-Time Files
I can't open some of the Project files!
- Do you have Visual Basic 6 installed on your PC?
Related Links
Using the Wedge to update a Web Page
(ASP)
Using the Wedge to update a Web Page
(HTML)
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