OPC UA FX requires more than just a Server with an OPC UA FX Information Model. All devices that implement the ConnectionManager are required to support Client functionality. This section will describe the requirements for this Client functionality. Some additional key points related to establishing a connection are:
- The Connection and security information may have changed since the engineering tool generated configuration information (ConnectionConfigurationSets).
- The ConnectionManager may be local on one of the devices, i.e., on the same device that has one end of a logical connection.
- The configuration might contain Nodes in any of the following formats: PortableNodeId, PortableRelativePath or AliasName, each of which has components that might have changed since they were generated by the engineering tool.
- System in which OPC UA FX is deployed may contain Global Services (GDS) that a ConnectionManager may be required to interact with.
- During the establishment of a logical connection (Connection), the ConnectionManager needs to locate the FunctionalEntities and the Servers on which they reside. The ConnectionConfigurationSets contain the information from which this location can be derived.
The ConnectionManager shall behave as a standard Client, including the ability to recover an interrupted Session if a Session is being used. A ConnectionManager may also use Session- less Service invocations in certain cases. The ConnectionManager is required to be able to issue Method Calls and also resolve Node information. Resolving Node information may require using View Services (Browse, TranslateBrowsePathsToNodeIds) and Attribute Services (Read). The details related to an application’s configuration are provided in a Descriptor, but the engineering tool associated with a ConnectionManager may not be able to resolve Node information beyond what is in the Descriptor, which results in a ConnectionManager requiring support for all of the Node resolution options.