Bounding value retrieval - query examples

You can use the Bounding Value retrieval mode to return a start bound point or an end bound point for a specified date and time. If no time is specified, Historian returns the bounding point at the current time.

To return a start bound point, set the following parameter in your query.

wwRetrievalMode = 'StartBound'

To return an end bound point, set the following parameter in your query.

wwRetrievalMode = 'EndBound'

Example 1 - Retrieve start bound point

select DateTime,TagName,Value

where TagName 'Plant2.R31.BatchNum'

and wwRetrievalMode = 'StartBound'

and DateTime >= '2019-04-24 12:00:00'

The results are:

Example 2 - Retrieve end bound point

select DateTime,TagName,Value

where TagName in 'Plant2.R31.BatchNum'

and wwRetrievalMode = 'EndBound'

and DateTime >= '2019-04-24 12:00:00'

The results are: