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<p class="head1" align="center"><font color="#990000" size="4" face="Arial"><b>OPC
Data Access 3.00 Sample Code</b></font></p>
<p class="head1" align="center"><b>
<font face="Arial" color="#800000">February 10, 2007</font></b></p>
<p><font face="Verdana" size="2"><a name="Overview"></a></font><b><font size="3" face="Arial">Overview</font></b></p>
<p><font face="Verdana" size="2">This version of the Data Access
3.00 Sample Code supports .NET 2.0 and has been tested on Windows
Vista. It also provides an updated
configuration tool for .NET based OPC server implementations.</font></p>
<p><font face="Verdana" size="2">The latest version of this document always on the
OPC foundation
<a href="http://www.opcfoundation.org/Downloads.aspx?CM=1&CN=KEY&CI=274&EBP=0&SRT=ModificationTime&DES=Y&SE1=ReleaseStatus&FV1=Released&FT1=&SE2=Title&FV2=Custom&FT2=%Sample%">website</a>.</font></p>
<p><font face="Verdana" size="2">Any use of the <i>OPC Data Access Sample Code</i> is
subject to the terms the <a href="http://opcfoundation.org/Downloads/LicenseAgreement.asp">
OPC Foundation License Agreement</a>.</font></p>
<p><font face="Verdana" size="2">The <i>OPC Data Access Sample Code</i>
consists of C# client and server applications and a C++ server
application. These applications implement the Data Access Custom
Interface Specification 3.00 and 2.05a. These samples are intended
to demonstrate the correct operation of the specification and to
serve as starting point for vendors who wish to develop their own
implementations.</font></p>
<p><font face="Verdana" size="2"><span style="mso-fareast-font-family: Times New Roman; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">The
sample client is written completely with .NET technologies; as a
result, it also demonstrates how to build .NET applications that
interoperate with existing OPC compliant COM servers. Part of the
sample client includes a set of classes and interfaces that expose a
common native .NET interface for both COM-DA and XML-DA servers.
This .NET API will be maintained a separate component that vendors
can use as a basis for their own .NET based applications.</span></font></p>
<p><font face="Verdana" size="2"><a name="Overview"></a></font><b><font size="3" face="Arial">DCOM
configuration with Windows XP SP2</font></b></p>
<p><font face="Verdana" size="2">Microsoft has provided some sample APIs
which can be used to programmatically configure DCOM permissions
under Windows XP SP2 and later systems. The sample code now includes
these APIs as part of the 'Sample Utility Classes' project. The APIs
are documented in the '</font><font face="Verdana" size="2">DCOM Config Readme.htm</font><font face="Verdana" size="2">'
file which is also part of that project.</font></p>
<p><font face="Verdana" size="2"><a name="Overview"></a></font><b><font size="3" face="Arial">Server
Implementation in .NET</font></b></p>
<p><font face="Verdana" size="2">The sample code includes a server implemented in C#. This server
is implemented using the .NET API server interface which is then
registered as an in process COM server. However, the .NET COM interoperability layer has a number of limitations that make it impossible to
develop a compliant DA server purely in .NET. As a result, the
sample code also includes a wrapper written in C++ that can host any
implementation of the DA interfaces in .NET. This wrapper is
designed to be generic and supports any .NET in-process server that
implements the DA COM interfaces. The XML configuration file for the
wrapper specifies the ProgID of the .NET server it loads.</font></p>
<p><font face="Verdana" size="2">Note that the .NET server
implementation uses same code base as the XML-DA sample server, as
result, this sample also demonstrates how to write a DA server in
.NET that supports both the COM DA and XML DA specifications.</font></p>
<p><font face="Verdana" size="2"><a name="Overview"></a></font><b><font size="3" face="Arial">Complex
Data</font></b></p>
<p><font face="Verdana" size="2">This version (3.00.2.02) of the sample clients
and servers have been modified to support the draft complex data
specification. Complex data related features are accessible in the
sample client user interface via context menus or buttons used to
view or edit an item value. If the item is a complex item (i.e. its
defines the complex data properties described in the specification)
then a complex item dialog will appear. This dialog displays the
complex data in its raw form (binary or text) as well as a tree
view. The type description information provided by the server is
also accessible via this dialog.</font></p>
<p><font face="Verdana" size="2">The underlying items exposed by the
sample servers are binary values which may be converted to XML by
server if requested by the client. The client application is able to
display a structured view of the complex data by fetching the OPC
Binary type description from the server and using this to parse the
buffer returned by the server.</font></p>
<p><font face="Verdana" size="2"><a name="Version"></a></font><b><font size="3" face="Arial">Version
History</font></b></p>
<table border="1" width="100%" cellspacing="0" cellpadding="2">
<tr>
<td align="center" bgcolor="#000080" width="99">
<b><font color="#ffffff" face="Verdana" size="2">Date</font></b>
</td>
<td align="center" bgcolor="#000080" width="90"><b><font color="#ffffff" face="Verdana" size="2">Version</font></b></td>
<td align="center" bgcolor="#000080">
<p align="center"><b><font color="#ffffff" face="Verdana" size="2">Description</font></b></p>
</td>
</tr>
<tr>
<td align="center" width="99"><font face="Verdana" size="2">2003-01-31</font></td>
<td align="center" width="90"><font face="Verdana" size="2">1.00.1.00</font></td>
<td align="left"><font face="Verdana" size="2">Released with an installation
program.</font></td>
</tr>
<tr>
<td align="center" width="99"><font face="Verdana" size="2">2003-02-02</font></td>
<td align="center" width="90"><font face="Verdana" size="2">1.01.1.00</font></td>
<td align="left"><font face="Verdana" size="2">Released with self-registration bug
fixes.</font></td>
</tr>
<tr>
<td align="center" width="99"><font face="Verdana" size="2">2003-02-14</font>
- 1
- 2
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