DAtoXi ExpressInterface (Xi / OPC .NET 3.0) Converter

The DAtoXi Converter is an OPC DA server that makes one Express Interface (Xi / OPC .NET 3.0) server accessible from OPC DA client applications. The DAtoXi Converter has a simple configuration and makes all DA objects of the Xi server accessible. The DAtoXi configuration can restrict the Xi server access to read-only. More detailed access restrictions can be defined in the configuration of the Advosol Xi servers. If data needs to be aggregated from multiple Xi servers then the OXS Exchange Server should be used instead. The HDAtoXi Historian Converter offers similar functionality for OPC HDA clients. To minimize DCOM issues the DAtoXi server should be installed on the same machine as the OPC DA client application. The remote communication then is through WCF and can be configured for the needed security level.

Xi Communication Security
The OPC Xi 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.

The Xi communication options are defined in the Xi server configuration.
Xi clients (DAtoXi) can only choose among the options defined in the server configuration. The DAtoXi configuration can define communication preferences as:
- Endpoint names
- Binding schemes (http, https, tcp)
- Secure yes/no
and the DAtoXi server at run-time selects the available endpoint that best matches the preference configuration.

The DAtoXi converter server is OPC Compliance tested in the configuration shown on the right. The OPC Compliance Tool (CTT) client accesses the Advosol DA Simulation server (built with the Advosol DANSrv OPC DA .Net Server Toolkit through the DAtoXi and XiTOCO converter servers. The CTT client calls all OPC DA specified methods with different arguements and checks the server response. Calls are also made with invalid arguments to check the server's error handling.

DAtoXi as a Tunneler or Security Gateway Solution
DAtoXi used in combination with the XiTOCO Converter wraps OPC DA to Xi and back to OPC DA. Remote OPC DA servers can be accessed through an Xi connection.

The Express Interface communication has significant advantages over Tunneler products: The communication can be configured to a security level appropriate for the application TCP or HTTP communication can be chosen. TCP communication offers high performance but requires firewall configuration. HTTP communication on standard ports works without configuration efforts. The standardized OPC .NET 3.0 interface is used instead of a proprietary Tunneler interface. Either side converter can easily be replaced with any Xi client respectively server.

Test the DAtoXi converter with Internet accessible Xi servers.

Xi Converter Products Comparison
Advosol offers multiple products with data aggregating and/or Xi converter features. The capabilities differ, allowing you to select the product best suited for you application needs.

Requirements

• Windows XP, Vista, Windows 7, Windows Server 2003/2008
• .NET 3.5 SP1 or 4.0 with WCF