OPC Server Toolkit
Change History
Added error notification callback to inform application of dcom errors which may occur in the OnDataChange Notification to connected client.
Miscellaneous changes to support latest edition of OPC Compliancy test. Added default EventAreaBrowser to allow ICONICS OPC DataSpy to work with WtOPCsvr based A&E Servers.
Added support for DA 3.0 SyncIO2::ReadMaxAge & ::WriteVQT Interfaces.
Corrected problem with user access security checking for the Data Access 3.0 ItemIO::Read and ::WriteVQT Interfaces.
Corrected ClassFactory operation that would result in intermittant start-up problems if server initiated by the client.
Added support for OPC Data Access 3.0.
Minor changes associated with supplying correct error return values for inappropriate client behavior as expected by the OPC Compliancy test.
Misc changes submitted by users. Initialized various floating pointers to NULL and wrapped COPCServer::ProcessAsyncIORequests() in structured exception handling. Put a check in CWTOPCsvrApp::CreateOPCCustomServer() to assure that the object was actually created. Added SetCaseSensitivity export to allow the server to ignore case when comparing tag names. Added logic to automatically refresh a group when it is made active via ::SetState. Added callback for A&E AckCondition.
Corrected CreateTag operation for IsWriteable flag. Additions of July 22 were creating all tags as writeable if Security option disabled.
Released security additions that allow user access checking for each tag.
Corrected the IOCItemProperties::QueryAvailableProperties return value for ppvtDataTypes. Corrected BSTR DataChange operations for OPC 1.0 Interfaces.
Added an application callback to allow a client to read the value of a tag using OPC_DS_DEVICE.
Changed Write Notification callback to allow the server application to perform an actual write to device, (with error checking), whenever a client writes an OPC tag. Also removed all exported functions from WtOPCsvr.dll that accepted CStrings as arguments and renamed those functions accepting LPCSTR for simplicity. WtOPCsvr.dll is not binary compatible with previous releases of the toolkit. Existing server applications must be recompiled with the new header file to access the new exported function list.
Corrected compliancy test issues--default timebias for AddGroup, returned error code for OPC_E_BADRIGHTS.
Corrected logic to release the HANDLE to server thread when a client disconnects.
Corrected Server update timer operation when running on Windows 95/98. Modified WriteItem callback logic to remove internal locks prior to making callback. Corrected Server shutdown logic.
Added C++ Callback Object definition for support of extended A&E Interfaces.
Added extra delay during shutdown to allow single-threaded server applications to close normally. Minor corrections to CIOPCGroupStateMgt::SetState Interface.
Corrected resolution of timestamp for data updates. A&E corrections to UpdateTagToList & SendAlarmMessagesFromList. Corrected redundant database locking calls. Added an extra API call that allows the dll to be initialized in the single-threaded COM model.
Corrected AddLocalServiceKeysToRegistry function. Check for VARIANT Type VT_NULL prior to attempting to change data written by client to the native type. (Client could not write an item unless the variant type was set by the server.)
Added API function for UserAEMessageEx to allow the application more control over event messages. Added an option to the OPC Write notification callback to prevent the dll from converting item data to it's native type prior to the callback.
Corrected problem with Alarms & Events Server operation during disconnect.
Corrected error in DataCallback procedure for OPC 1.0 connections.
Minor changes to correct error responses as expected by latest version of OPC Compliancy test.
Released version 4.0 containing options for more efficent updates of server tags. Optional support provided for string hashing and updating multiple tags at once. Added new example application to demonstrate optimizations for servers containing a large number of tags.
Corrected error return values from various Interface functions to conform to those expected by OPC Foundation Compliancy test. Corrected GPFault exception conditions in GroupEnumerator.Next() and CloneGroup() functions. Added String Enumeration for Group Names. Corrected logic error in QueryInterface functions for all ConnectionPoint Interfaces. Modified design to allow simultaneous OPC 1.0 & OPC 2.0 connections to the same group.
Modified design to create seperate client thread for each connection. Corrected Item List locking logic to keep from locking database during callback notification to a client. Added SuspendItemUpdate() API to allow a server application to use dynamically created tags while maintaining the automatic item browsing feature of the dll.
Added API function to WtOPCSvr DLL to UninitWTOPCsvr(). This function calls CoUninitialize() to cleanup DCOM initialization. CoUninitialize() was previously being called in the destructor of the DLL and was generating an exception if the server was closed with open client connections.
Reversed change of May 30 that automatically added the AppId\...\LocalService Key to the Windows Registry. Added a separate function (AddLocalServiceKeysToRegistry) to be used for registering NT Services.
Corrected Server call to ShutdownRequest, (IOPCShutdown interface). Was passing a NULL pointer-- should have been a pointer to a NULL.
Added callback function to notify application when last client disconnects. Also modified registry functions to update AppID\LocalService key.
Replaced SetItemPropertiesA() function with a more generic SetItemProperties() that allows the server to configure custom properties for each OPC Item.
Added a Description and Engineering Units to Item Properties. Corrected error in CIOPCItemProperties::GetItemProperties Interface. Modified VB Server example for Write Callback Notification.
Re-Enabled debug event messages from the server, (They had been inadvertantly removed in a prior release).
Added Visual Basic example application to OPC Server toolkit.
Corrected return value from AddItems if not all requested items could be added. Now returns S_FALSE. Previously returned E_FAIL.
Added support for OPC Alarms & Events.
Added logic to WtOPCSvr.DLL that allows a server application to dynamically add and remove tags as requested by clients. (Special Thanks to A.J. Johnson of Telepro Inc.)
WtOPCSvr.DLL modified to simplify critical-section access to OPC Item and Tag data. This prevents possible deadlock condition on writes from connected clients.
WtOPCSvr.DLL corrected problem with memory allocation/deallocation of String Tags. Was not calling VariantCopy in all cases and the same string memory was being used in multiple places.
WtOPCsvr.DLL corrected ValidateItem() interface. Was previously returning default values for AccessCode and DataType.
Changed timer operation in WTOPVsvr.dll to create a separate thread for triggering updates to clients. Previous design was not triggering the timer if The calling thread, (that which called InitOPCsvr()), did not contain a Windows Message Processing loop.
WTOPCsvr.dll modified to provide additional function for Updating the Timestamp of a tag.
WTOPCSvr dll modified to handle Cstring arguments differently. It is not a recommended Microsoft practice to pass Cstrings as arguments. They get the reference counts messed up. Code was changed to convert the Cstrings to byte strings and then back to Cstrings for internal use by the dll. This seems to correct the exception message generated by debug versions of the application when closing.
WTOPCSvr initialization changed to allow failures in the DCOM initialization call. If the control App initializes COM first, (AfxOLEInit()), prior to calling initWtOPCSvr(), then the dll initialization may fail because it’s trying to initialize DCOM as Free-Threaded after the App has already set it to Apartment-Threaded.
WTOPCSvr modified to support strings for OPC 1.0 connections.
WTOPCSvr logic corrected for Async Write notification to return Client Handle rather than Server Handle. (Works with GraphWorx)
WtOPCSvr.DLL corrected AddItems() method. Was previously returning wrong item handle if multiple items were added with single command.
OPC Client Toolkit
Change History
Changed ReadItemFromDevice to return HRESULT rather than BOOL.
Added api export to change an item's active state, (ChangeOPCItemState).
Added api exports to utilize Data Access 3.0 ItemIO::Read and ::WriteVQT functions.
Added an extended data change callback to include the Connection Handle which allows more efficient operation for multi-threaded applications.
Corrected logic race condition if multiple threads called DisconnectOPC at the same time.
Corrected memory leak in ReadOPCItemFromDevice function.
Corrected problem with trying to release memory from a failed call to SetClientHandles and SetActiveState.
Corrected memory leak on Write failure, (Needed to free memory for pErrList if ->Write returns S_FALSE)
Additional exports added to call raw A&E Interfaces.
Corrected browsing errors associated with wide character additions of June 20.
Corrected some memory leaks associated with ItemProperties. Added code to accomidate wide character tag names.
Added extended export for BrowseOPCItemIDs.
Added extended exports for ChangeBrowsePosition and SyncIOWrite.
Corrected error return value for QualifyItemName export. Corrected Browsing operation for Tags that end with '.'
Added callback for Asynchronous write operations. Changes return value for WriteOPCItem to reflect error condition returned from server.
Added API function to export functionality of GetItemID to allow client to obtain the fully qualified node name from the connected server.
Added API function to allow the application to read an item directly from the server using the SyncIO Interface, (ReadOPCItemFromDevice(...)).
Corrected internal buffering, (ReadOPCItem), operation to work with user defined update tags, (SetItemUpdateHandle).
Added API call to allow application to change the group active/inactive state.
Corrected expanded A&E function prototypes to include WINAPI macro to match VB mangled name convention. Corrected DA browsing operation to reset node to "Root" before executing GetItemList function. Modified browsing logic to try both Unqualified and Qualified node names for BrowseDown operations.
Added API functions for calling the raw interfaces of an A&E Server to RequestRefresh(), AckCondition(), EnableConditionByArea(), EnableConditionBySource(), DisableConditionByArea(), DisableConditionBySource(), GetFilter(), and SetFilter().
Added ability to connect to InProc Servers
Added new exported function to ConvertFileTimeToVBDate(). This allows Visual Basic applications to use the OPC FILETIME timestamp returned by ReadOPCItem().
Added support for basic Alarms & Events operation.
Added additional API calls to provide better control over browsing operations, including setting filters. Provided support for reading OPC Item properties and setting the Client Handle for an OPC item. Generated a new example MFC application to demonstrate new features.
Corrected CLSID lookup logic for remote servers.
Added RefreshOPCGroup() API to allow the client application to request a refresh from the server.
Added "Handle to Connection" for application callback for Server requested shutdown.
Added support for the IOPCShutdown Interface with callback to application whenever a connected server requests to disocnnect. Also increased error checking for valid interface pointers prior to use.
Added exported API function to AddOPCItemWithPath(). Also provided callback for error display rather than using MessageBox within DLL.
Added exported API function to GetOPCItemNameFromHandle().
Removed DCOM initialization from DLLMain and created seperate API function. This eliminates potential problems with DLL load order and allows the client application flexibility to initialize NT security as required
Corrected uninitialized pointer which would result in an Exception if CoCreateInstance() failed, (i.e. Server could not be started).
Corrected logic to check for individual error return values for each item returned from AddItems function.
Added an extra function to WTClient.DLL to call OPC_Common SetClientName(). Also revised OPC 2.0 DataCallBack to exclude item data if server supplied *pError is not S_OK.
Added an extra function to WTClient.DLL to force a connection to operate as an OPC 1.0a IAdvise connection.
Corrected problem with interface to Iconics Server, whereby only one item in a group would be updated.
NumberOfOPCServers() function was not clearing the ServerList Array upon entry, resulting in multiple entries for each installed server if called recursively.
Fixed memory leak in WriteOPCItem function.
The Visual Basic example application supplied with the WTClient toolkit contained errors in the function prototype declarations in module1.bas. All Integer arguments in module1.bas should have been Long. Visual Basic Integer types are only 16-bits wide and all values passed into WTClient.dll should be 32-bit integers.
The WTClient.DLL was modified to correct a problem with Visual Basic 6.0 generating an error on CoUninitialize() whenever the dll was unloaded.
Wtclient.DLL modified to add an API function to GetItemType().
WTClient.DLL modified to enhance browsing operations. Corrected logic to prevent exception if the Browse Down function fails. Also modified code to try the BrowseDown function using the node name and if that fails, try the fully qualified name.
Modified Wtclient toolkit to allow multiple asynchronous connections.
Last Updated: April 30, 2006
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