Reads one or more values, qualities and timestamps for the items specified. This is functionally similar
to the OPCSyncIO::Read method except it is asynchronous and no source is specified (DEVICE or
CACHE). The server will make the determination as whether the information will be obtained from
the device or cache. This decision will be based upon the MaxAge parameter. If the information in
the cache is within the MaxAge, then the data will be obtained from the cache, otherwise the server
must access the device for the requested information.
Syntax
Visual Basic (Declaration) | |
---|
Public Overloads Function ReadMaxAge( _
ByVal items() As ItemValue _
) As Integer
|
Parameters
- items
- Holds the server handle as the item identifier on entry and the read
value/quality/timestamp or error on return.
Return Value
HRESULT success/error code
Requirements
Target Platforms: Windows 7/8/10, Windows Server 2003/2008/2012/2016, .NET 4.x
See Also