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.
Overload List
| Overload | Description |
|---|---|
| ReadProcessed(DateTime,DateTime,TimeSpan,Int32[],Int32[],OPCHDAItem[],Int32[]) | Synchronous ReadProcessed. 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. |
| ReadProcessed(Int32,DateTime,DateTime,TimeSpan,Int32[],Int32[],Int32,Int32[]) | Asynchronous ReadProcessed. 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, et. al. for each item during the specified time domain when resampleInterval is 1 hour. The results are returned via the client's IOPCHDA_DataCallback::OnReadComplete method. |
Requirements
Target Platforms: Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows 7, Windows Server 2008 family