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. 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. 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. 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. 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. 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. 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. 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. OPC Server configuration and data access handling. 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
Visual Basic (Declaration) | |
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Public Class AppPluginHDA Inherits HdaGenericServer |
C# | |
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public class AppPluginHDA : HdaGenericServer |
System.Object
HDAPluginDA.HdaGenericServer
HDAPluginDA.AppPluginHDA
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2