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About OPC Unified Architecture

The OPC Unified Architecture (OPC UA) standard combines all the capabilities of OPC Data Access and OPC Historical Data Access standards (together, referred to as "OPC Classic") and adds various additional capabilities into a single, extensible standard. OPC UA servers provide a single namespace which organizes the data available on the server into a hierarchical view of nodes (also called items in OPC Classic terminology). Nodes on OPC UA servers can be object nodes, variable nodes, or method nodes. Object nodes help to organize other nodes. Variable nodes store values which represent some process value on the server. These nodes can also contain other variable nodes. Method nodes represent function calls for object specific processes. Nodes are arranged in a number of representations; for Industrial Communication Toolbox™, the nodes are exposed as a hierarchical tree, with nodes containing subnodes called children.

OPC UA servers are required to publish a node in their namespace named "Server". The Server node provides information about the OPC UA server, including the capabilities of the server, specific limitations of the server, and other information related to the server. Industrial Communication Toolbox provides selected information from the Server node as properties of the client you create to connect to that server. For information on client properties, see

OPC UA servers may or may not historize Variable nodes. For historizing nodes, OPC UA servers store prior values of the node, and can provide that history to OPC UA Clients as raw data (data points at the times that the server stored the Value), or as data at requested times (the server interpolates the raw data using either sample-and-hold or linear interpolation), or as processed data, using a predefined aggregate function that is requested by the user. Each OPC UA server describes which Aggregate Functions are supported by that server. "OPC UA Aggregate Functions" describes the standard aggregate functions defined in the OPC UA specification. Servers may implement custom aggregate functions; consult the specific OPC UA server reference for information on how those functions work. Industrial Communication Toolbox provides a client interface to the OPC UA servers which allows you to browse the server namespace to find nodes of interest. The toolbox supports the opc.tcp binary protocol and anonymous, unsecured connections. You can also use the client to define the security configuration for the connection, and provide user credentials to the server. The toolbox supports the opc.tcp binary protocol only; HTTP and HTTPS connections are not supported. For some of the tasks you can perform with Industrial Communication Toolbox, see the related examples.

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