1.3.2.2 Web Server

WebAccess uses an ordinary web server as our Project Node.

Microsoft IIS (Internet Information Server) is a standard option in Windows 2000 Professional and Server, XP Professional and Server 2003.

The Project Node provides the initial link between Clients and the SCADA nodes.  After that link, the Web browser clients communicate directly to the SCADA Node.  The connection to the Project Node is dropped until the Refresh button is pressed (which not normally done while using WebAccess).  The 10 simultaneous connections provided by Windows 2000 and XP Professional will support much more than 10 users of VIEW (the runtime version). However, only 10 could be simultaneous users of the Project Manager (the configuration tool).

Usually, only the Project Node is a Web Server.  Usually SCADA nodes are not web servers. Exceptions are:

Stand-alone installations where the Project Node and SCADA node are combined on one PC.

Use of bwView.htm to allow direct connection to SCADA node.  This might be done for reliability or throughput reasons. (See the Engineering Manual section 16.1.2 BwView.htm - connect without a Project Node) .

This makes WebAccess a "fully" web-based solution.  WebAccess enables engineers, integrators and vendors with the ability to support their systems remotely over an intranet or the Internet using an ordinary web browser.

Note -  it is also possible for Clients to connect to the SCADA Node without using a web server if the"deploy file" is distributed to clients in some way (see the Engineering Manual section 16.1.3.1  BwView.htm - connect without a Web Server).  

A web server is always required for the configuration tool (the Project Manager) and logging to an ODBC database.

ASP (Active Server Pages) are used as the Engineering Tool in WebAccess, for HTML reports, and initial client connections. An ASP enabled Web Server is required. Microsoft IIS is the only ASP enabled Web Server software  supported by WebAccess SCADA and HMI software.

For More information see Project Node System Requirements and IIS on the Project Node.  To Determine if IIS is installed on your Project Node computer see the Troubleshooting section.