ReadAttributes handling. The data is read from the database and returned in OPC HDA compliant form according the client call parameters. In most application it should only be necessary to adapt the GetItemData() method. OPC Server configuration and data access handling. Handles asynchronous Update client calls. The requests are queued and executed in the queued sequence by the handling thread. Some application may need more than one thread for improved throughput. In such a case this class needs to be modified, otherwise typically not. Handles asynchronous Annotations client calls. The client calls are queued and processed in the handler thread. The actual database access is handled in the Annotations class. Some application may need more than one handler thread to improve throughput. In such a case this class needs to be modified, otherwise typically not. Annotations read and insert handling. These methods are called either from: - the client call handling for synchronuos calls - the annotation handling thread for asynchronus calls Handles Playback client requests. The actual database reading is done in the DataRaw.cs, DataProcessed.cs All Playback handling is done in a single thread. Some application may need more threads to improve throughput. In such a case this class needs to be modified, otherwise typically not. ReadProcessed handling. The data is read from the database and returned in OPC HDA compliant form according the client call parameters. In most application it should only be necessary to adapt the GetItemData() method. This class handles asynchronous Read and Advise client calls. The actual database reading is done in the DataRaw.cs, DataProcessed.cs, DataModified.cs, DataAtTime.cs, DataAttributes.cs modules.
There are two threads for:
- handling of asynchronous read calls
- Advise handling
Some application may need more threads to improve throughput. In such a case this class needs to be modified, otherwise typically not. ReadModified handling. The data is read from the database and returned in OPC HDA compliant form according the client call parameters. In most application it should only be necessary to adapt the GetItemData() method. ReadRaw handling. The data is read from the database and returned in OPC HDA compliant form according the client call parameters. In most application it should only be necessary to adapt the GetItemData() method. ReadAtTime handling. The data is read from the database and returned in OPC HDA compliant form according the client call parameters. In most application it should only be necessary to adapt the GetItemData() method. Update handling. The methods update the database by inserting, replacing or deleting data points. These methods are called either from: - the client call handling for synchronuos calls - the update handling thread for asynchronuos calls

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See Also