This method computes aggregate values, qualities, and timestamps from data in the history database for the specified time domain for one or more items. The time domain is divided into subintervals of duration resampleInterval. The specified aggregate is calculated for each subinterval beginning with startTime by using the data within the next resampleInterval. This method is intended to provide values calculated with respect to the resample interval. For example, This method can provide hourly statistics such as Maximum, Minimum, Average, etc. for each item during the specified time domain when resampleInterval is 1 hour.
Syntax
| Visual Basic (Declaration) | |
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Overloads Function ReadProcessed( _ ByVal startTime As Date, _ ByVal endTime As Date, _ ByVal interval As TimeSpan, _ ByVal serverHandles() As Integer, _ ByVal aggregates() As Integer, _ ByRef itemValues As OPCHDAItem(), _ ByRef errors As Integer() _ ) As Integer | |
| C# | |
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int ReadProcessed( DateTime startTime, DateTime endTime, TimeSpan interval, int[] serverHandles, int[] aggregates, out OPCHDAItem[] itemValues, out int[] errors ) | |
Parameters
- startTime
- The beginning of the history period to be read.
- endTime
- The end of the history period to be read.
- interval
- Interval between returned values.
- serverHandles
- The list of server item handles for the items to be read.
- aggregates
- The calculation to be performed on the raw data to create the values to be returned.
- itemValues
- OUT: Array of objects in which the item values are returned. The order of the objects in the array shall be the same as the order of the server item handles.
- errors
- Array of HRESULTs indicating the success of the individual item reads. The errors correspond to the handles passed in phServer. This indicates whether the read succeeded in obtaining defined values, qualities and timestamps. NOTE any FAILED error code indicates that the contents of the corresponding OPCHDAItem structure are UNDEFINED.
Return Value
HRESULTS success/error code.Requirements
Target Platforms: Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows 7, Windows Server 2008 family