Delta
The Delta algorithm retrieves the difference between the earliest and latest raw values for the resample interval. If the last value is less than the first value, the result will be negative. If the last value is the same as the first value, or if the last value is also the first value at the same timestamp, the result will be zero. If the last value is greater than the first value, the result will be positive.
The results returned by the algorithm do not depend on the quality of the data. You can choose to filter the data on quality using the Qualities combo box in the Edit Source window (see Configure a Trace)
Unless otherwise indicated, Geo SCADA Expert uses worst quality from the two values. If the quality filter is good then the result will also be good, but if the quality filter includes uncertain / bad values then the result may be uncertain / bad if the earliest / latest values are uncertain or bad.
The time stamp of the result matches the start time of the resample interval.
Further Information