Historians can include the ability to process raw data in a variety of ways before returning it to you. Examples of such processing include the interpolation of data points, time averaging, and standard deviation calculations. Processing of data can be very useful when there is a large amount of data on the server. Instructing the server to return only a processed data set can greatly reduce the time and volume of data transferred.
|Read data from an OPC HDA server at specified times|
|Read server-aggregated data from an OPC HDA server|
|Get description of OPC HDA aggregate type or item attribute|
|Translate OPC HDA aggregate type or item attribute name to numeric identifier|
|Get all aggregate type or item attribute IDs|
|Get all aggregate type or item attribute names|
- Read Historical Data at Specific Times
Read values for a list of items at specific times.
- Read Processed Aggregate Data
Instruct the server to return only a processed data set.