Limitations

When retrieving data from the Historian, the request can time out if it takes too long to get the data. By default, the timeout setting is 60 seconds. To change this setting, in the Historian Administrator click the Data Stores link at the top. Under the Global Options tab, in the Data Queries section, change Maximum Query Time (seconds). Click Update when finished.

Calculated and Sampled Values

When retrieving calculated or sampled values from Historian there is a limit to the amount of values that can be returned. By default, this is 100,000. To change this setting, in the Historian Administrator click the Data Stores link at the top. Under the Global Options tab, in the Data Queries section, change Maximum Query Intervals. Click Update when finished.

Note that this is a value count and not a row count. For example, to retrieve 1 second values for 2 tags, 172,800 values are retrieved (86,400 * 2) so just for this request; the default limit would have to be increased.