The Interpolative Aggregate defined in Table 15 returns the Interpolated Bounding Value (see 3.1.8) for the startTime of each interval.

When searching for Good values before or after the bounding value, the time period searched is Server specific, but the Server should search a time range which is at least the size of the ProcessingInterval.

Table 15 – Interpolative Aggregate summary

Interpolated Aggregate Characteristics



Data Type

Same as Source

Use Bounds




Status Code Calculations

Calculation Method


Good if no Bad values skipped and Good values are used, Uncertain if Bad values skipped or if Uncertain values are used. If no starting value then Bad_NoData. See description of Interpolated Bounds (see 3.1.8) for more details


Not Set

Calculated bit

Not Set

Interpolated bit

Set Sometimes

Always set except for when the Raw bit is set

Raw bit

Set Sometimes

If a value exists with the exact time of interval Start

Multi Value bit

Not Set

Status Code Common Special Cases

Before Start of Data

Return Bad_NoData

After End of Data

Return extrapolated value (see 3.1.8) (sloped or stepped according to settings)

Status code is Uncertain_DataSubNormal.

Start Bound Not Found


End Bound Not Found

See “After End of Data”

Bound Bad

Does not return a Bad bound except as noted above

Bound Uncertain

Returned Uncertain_DataSubNormal if any Bad value(s) was/were skipped to calculate the bounding value.