Hello,,

there is no standardized way in OPC Classic to retrieve array dimensions. The only way to do it is to actually read the array item (or subscribe to it), and then, when you get the array value, you will be able to get its dimensions using normal means.

VarType.NumericalValue is documented as "The numerical (integer) value of the data type.". It is the same thing information as in VarType.InternalValue, but expressed as a number (bit mask). It does not contain more or different information from InternalValue. The actual numerical values are documented in Windows, e.g. docs.microsoft.com/en-us/openspecs/windows_protocols/ms-oaut...9f-5803-4dc4-9d14-5425d3f5461f , but normally you should have no need to use this property.

The "type mismatch" error you get in Demo app originates in the server, not in the client. It appears because the "RegisterXXXX" items do not have any initial contents in them. If you write the array into such item first, you will then be able to read it. But the Demo app does not have the ability to write arrays.

Best regards