Counter retrieval - query example

To use the counter mode, set the following parameter in your query.

wwRetrievalMode = 'Counter'

In the following example, the rollover value for the SysTimeSec system tag is set to 0. In a two-minute time span, the SysTimeSec tag increments from 0 to 59 two times. The following query returns the total count within the two-minute time span. The QualityDetail of 212 indicates that a counter rollover occurred during the query time range.

select DateTime, TagName, Value, Quality, QualityDetail as QD from History

where TagName = 'systimesec'

and DateTime >= '2009-08-13 1:00'

and DateTime < '2009-08-13 1:02'

and wwRetrievalMode = 'counter'

and wwCycleCount = 1

The results are: