DWIS.Client.ReferenceImplementation.OPCFoundation 2.2.56

DWIS Blackboard client

Release 2.2.53

Updates the DWIS semantic package dependencies to 2.2.34. The core, OPC Foundation and Unified Automation client packages use the same release version; transport packages depend on core version 2.2.53. Other runtime dependencies are unchanged.

OPC Foundation client 2.2.54 adds ConfigureDataSubscription(publishingInterval, samplingInterval) using TimeSpan values. Call after connection and before Subscribe to avoid the default 100 ms data cadence when slower signals suffice. Both intervals must be at least one millisecond and fit an Int32 millisecond value. Existing subscriptions can also be reconfigured. Semantic query subscription cadence is independent; unchanged callers retain existing behavior. Reapply configuration after session replacement.

The OPC Foundation client also implements IDisposable. Dispose it when its owner finishes to close the UA session and remove server subscriptions promptly. Do not reuse a disposed instance; create a new client for the next session.

Query lifecycle (prepared OPC Foundation client 2.2.55)

Identical query text, trimming outer whitespace only, shares one server registration and one monitored item per client session. Repeating the same query/callback performs no additional server call. Different callbacks share that item and receive a current initial snapshot in the registration return value. Exceptions from one callback do not stop other callbacks.

UnregisterQuery(sparql, callback) removes one callback; UnregisterQuery(sparql) removes all. The last callback releases that session's server ownership and removes its monitored item. Dispose clients to release registrations, delete subscriptions and close their sessions. Session replacement clears stale query/data/acquisition callback handles and provided-variable caches; callers rebuild subscriptions after reconnect. New sessions request a two-minute timeout, subject to server limits. This does not add automatic subscription restoration.

The upgraded Blackboard shares query evaluation across sessions but keeps notification nodes and initial results independent. It cleans up registrations on session close or expiration. The additive OPC-UA UnregisterQuery method accepts a one-element String array and releases only the calling session's ownership. With an older server the client still deduplicates locally, but complete server cleanup requires the server upgrade. Other language clients and the Unified Automation C# transport are unchanged; upgraded servers still clean up their closed sessions.

For isolated integration tests set DWIS_QUERY_LIFECYCLE_ENDPOINT to a loopback test endpoint outside normal port 48030 and run the C# test project. The tests use dedicated temporary PKI/log paths and verify repeated registration, independent callbacks, two clients, owner release, repeated disposal, legacy session-close cleanup, and re-registration after session replacement. Never use the shared Blackboard. No NuGet package has been published for this prepared change.