The uaPLUS server plug-in is working in different operating modes, depending on the values returned in the GetServerParameters() method:
| Browse Mode |
Defines how client browse calls are handled.
| Real |
All browse calls are handled in the generic server according he items defined in the server cache.
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| Virtual |
All client browse calls are handled in this plug-in and typically return the items that are or could be dynamically added to the server cache.
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| Item Validate Mode |
Controls how the generic server handles the ValidateItems client calls.
| UnknownItems |
The plug-in ValidateItems method is called for items that are not found in the generic server cache.
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| Never |
The plug-in ValidateItems method is NEVER called. Requested items that are not defined in the generic server cache are treated as unknown items.
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| Always |
The plug-in ValidateItems method is ALWAYS called. This allows the plug-in to determine the items access rights based on the client's credentials and return OPC_E_UNKNOWNITEMID for clients without the required privileges.
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| Write Cache Update |
Defines how the generic server handles the cache in OPC client write calls. The DANSrv Standard Edition supports only the Generic mode.
| Generic |
The generic server writes the item values into the cache.
This is done after calling the customization WriteItems method and is done only for items that were successfully handled in the customization module and no error was returned.
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| Custom |
The generic server does NOT write the value into the cache. The customization module WriteItems method must update the cache by calling the SetItemValue callback method. This allows the customization module to modify the value and update the cache with the value that is actually written to the device.
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