The TimeAverage Aggregate defined in Table 17 uses Interpolated Bounding Values (see 3.1.8) to find the value of a point at the beginning and end of an interval. Starting at the starting bounding value a straight line is drawn between each value in the interval ending at the ending bounding value (see examples for illustrations). The area under the lines is divided by the length of the ProcessingInterval to yield the average. Note that this calculation always uses a sloped line between points; TimeAverage2 uses a stepped or sloped line depending on the value of the Stepped Property for the Variable.

If one or more Bad Values exist in the interval then they are omitted from the calculation and the StatusCode is set to Uncertain_DataSubNormal. Sloped lines are drawn between the Good values when calculating the area.

The time resolution used in this calculation is Server specific.

Table 17 – TimeAverage Aggregate summary

TimeAverage Aggregate Characteristics

Type

Calculated

Data Type

Double

Use Bounds

Interpolated

Timestamp

StartTime

Status Code Calculations

Calculation Method

Custom

Good if no Bad values skipped and Good values are used, Uncertain if Bad values are skipped or if Uncertain values are used

Partial

Set Sometimes

If an interval is not a complete interval

Calculated

Set Always

Interpolated

Not Set

Raw

Not Set

Multi Value

Not Set

Status Code Common Special Cases

Before Start of Data

Bad_NoData

After End of Data

Value extrapolated, Uncertain status

No Start Bound

Calculate Partial Interval

No End Bound

Extrapolate data, Uncertain status

Bound Bad

NA

Bound Uncertain

NA