Express Interface Information about the OPC Xi Specification and OPC Xi Products
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The OPC Foundation adopted the Express Interface as the OPC .NET interface that bridges the gap between Microsoft .NET and the world of OPC Classic.

OPC .NET defines a .NET API for the Express Interface.

OPC Foundation members can download sample implementations of servers and clients.

The code includes a wrapper server for OPC DA, HDA, AE and the OPC .NET client API (core client code) with sample client applications.

Visit the OPC Foundation web site for more information.

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The Express Interface (Xi) is a public domain specification that provides a simple .NET communication interface for OPC Classic servers. Xi is based on the Windows Communication Foundation (WCF) and defines a formal interface that combines the semantics of OPC DA, OPC A&E, and OPC HDA into a single interface and provides additional support for historical alarms and events.
The Express Interface is the result of a collaboration among several OPC vendor companies and was developed to allow client applications to easily use .NET to access existing OPC Classic servers.

Xi / OPC .NET 3.0 Overview

The use of WCF allows for simple implementations of Express Interface (Xi) servers and clients. The Windows Communication Foundation handles all communication aspects with a wide range options for local and remote connections and is available on all .NET platforms including the .NET Compact Framework and Silverlight.
WCF provides a high level of security through built-in authentication, authorization and data encryption. It also simplifies access through firewalls.
Additional security features have been built into the Express Interface to enable secure server access with high performance.

The Xi specification and server reference base code are available under the Express Interface public license.


Xi Vendors

Advosol Inc.

Emerson DeltaV




MYNAH Technologies


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