XiPLUS ExpressInterface (Xi / OPC .NET 3.0) Server Toolkit

The XiPLUS server toolkit makes the development of ExpressInterface (Xi / OPC .NET 3.0) servers quick and simple. The generic Xi server handles the Xi interface and ensures interoperability. The application specific server part is in a plug-in DLL that can handle any kind of devices. This Net assembly is built with C# otr VB.NET.

The XiPLUS generic server is designed to work with the same plug-in DLL as the Advosol .Net server toolkits for classic OPC:

• DANSrv OPC DA .NET Server Toolkit
• DANsrvAE OPC A&E option for DANSrv
• HDANSrv OPC Historian Server Toolkit

This has the important advantages:

• Users of the Advosol .NET server toolkits can use their existing server plug-in DLLs with the Xi generic server and get Xi servers without software development effort.
• A decision for either OPC DA or OPC Xi has NOT to be made. Server providers can deliver their servers as DA or Xi servers depending on what the customers request.
• There is no performance tradeoff as in an approach with wrapper servers. The Xi server completely eliminates the troublesome DCOM.

The server developer only has to implement the plug-in .NET assemblies with the server configuration and the 'device' handling. No Xi knowledge is required. Actually the plug-in DLLs can also be used with the Advosol.NET server toolkits for classic (DCOM based) OPC servers. The plug-in interface is easy to implement, high performance and flexible enough for complex servers. Server Development Xi servers can be developed with Visual Studio 2005, 2008 or 2010 in C# of VB.NET for either .Net3.5 or 4.0. New server projects can be: Created with the XiPLUS template in the Visual Studio New Projct wizard The XiPLUS wizard shows a dialog and lets the user select the functionality of the created code. Base on one of the provided sample servers.

Sample Servers

Several sample servers are provided as a Visual Studio solution.
The servers are kept simple so that they are easy to understand and adapt. Each server is designed to show a particular feature.
Users can select one of the sample servers as the base for their project. Missing features can be copied form the other sample servers.

Tools

Xi Server Features

The XiPLUS generic server supports the Data Access, Events and Journal (History) Xi feature set.
XiPLUS is a fully managed application that runs in 32bit and 64bit mode.
The XiPLUS server is provided:

• as an EXE file that can be started as a:
  • Process (console application)
  • Windows Service
• as a DLL for embedding into user .NET applications.

Xi Security
The Express Interface specification was designed with communication security as a main consideration. Management and data read/write operations are handled through different endpoints, which can be separately configured with appropriate communication settings. Xi management methods associate handles with object identifiers and the read/write data methods only communicate handles with the data. This makes data hard to interpret by an eavesdropper even if it's communicated without encryption.
Xi servers usually require only the management endpoint to be configured for secure communication. This ensures good security without reducing the data exchange performance.

Access control on Object level The Xi interface and WCF security control the access to the server. Clients that are allowed access to the server have access to all objects of the server. The Advosol Xi servers implement an additional security layer. The server configuration can restrict the object access individually for each client. Browsing the server shows only the objects this client is allowed to access. The screen shots on the right show the object structure of the same Xi server for different clients. The server is configured to allow one client access to all objects but to allow other clients only read access to a few objects. The clients are identified by either the Windows user name or by a X509 certificate. Access can further be restricted to a particular client IPC address. The access rights can be restricted to e.g. deny write access, deny access to a set of object or allow access to only a configured set of objects. The XiConfig utility provided with the Advosol Xi servers makes the server configuration simple. All configuration and security settings can be made with this one utility. XiConfig also supports the creation and management of X509 certificates. Object access restrictions can be interactively edited. The Xi server can be browsed and dragged to a list of objects that are either allowed or blocked for particular clients. The configuration is stored in an XML file that is processed by the server at startup.	Client with full access rights	Client with read-only access to an object subset.

Requirements

• The Xi client/server communication bases on WCF (Windows Communicaton Foundation) and requires .NET 3.5 or newer with activated WCF.
• The Xi server discovery bases on PNRP, which is default installed in Windows Vista and Windows 7 but needs to be downloaded for XP. PNRP also requires IPV6 being activated.
• Visual Studio 2005, 2008 or 2010 with C# or VB.NET

Downloads

Download the evaluation for the setup file with the code and the utilities.
The Download with the license is a key file that needs to be copied into the folder with the XiPLUS executable. The key file needs to be distributed with the server executables.
The key file must match the version of the XiPLUS.exe file. It unlocks only exe files of the same or older version.

.NET applications can access OPC AE server through a set of conveniant classes and methods. The EventView control handles a wide range of OPC Alarms&Events viewing requirements. OPC Alarms&Events .NET clients can be created without writing code and without knowledge of the OCP AE specification.