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AF SDK Reference

PIPoint.InterpolatedValues Method

  • Last UpdatedNov 18, 2025
  • 4 minute read
PIPoint.InterpolatedValues Method
Retrieves interpolated values over the specified time range at the specified sampling interval.

Namespace:  OSIsoft.AF.PI
Assembly:  OSIsoft.AFSDK (in OSIsoft.AFSDK.dll) Version: 3.1.1.1182

Syntax

public AFValues InterpolatedValues(
	AFTimeRange timeRange,
	AFTimeSpan interval,
	string filterExpression,
	bool includeFilteredValues
)
Public Function InterpolatedValues ( 
	timeRange As AFTimeRange,
	interval As AFTimeSpan,
	filterExpression As String,
	includeFilteredValues As Boolean
) As AFValues

Dim instance As PIPoint
Dim timeRange As AFTimeRange
Dim interval As AFTimeSpan
Dim filterExpression As String
Dim includeFilteredValues As Boolean
Dim returnValue As AFValues

returnValue = instance.InterpolatedValues(timeRange, 
	interval, filterExpression, includeFilteredValues)
public:
AFValues^ InterpolatedValues(
	AFTimeRange timeRange, 
	AFTimeSpan interval, 
	String^ filterExpression, 
	bool includeFilteredValues
)
member InterpolatedValues : 
        timeRange : AFTimeRange * 
        interval : AFTimeSpan * 
        filterExpression : string * 
        includeFilteredValues : bool -> AFValues 

Parameters

timeRange
Type: OSIsoft.AF.TimeAFTimeRange
The bounding time range for the interpolated values request. If the StartTime is earlier than the EndTime, the resulting values will be in time-ascending order, otherwise they will be in time-descending order.
interval
Type: OSIsoft.AF.TimeAFTimeSpan

The Sample interval. If specified in hours, minutes, seconds, or milliseconds, the time intervals will be evenly spaced UTC time intervals. Longer interval types are interpreted using wall clock rules and are time zone dependent. For example, an interval created with the string "24h" means using an evenly spaced 24 UTC hour interval between each event. On the other hand, an interval created with the string "1d" would return an interval shorter or longer than 24 hours if the interval encompasses a Daylight Savings Time change.

When a positive interval is specified, the interval calculation begins at the earliest bounding time in the timeRange and applies the interval repeatedly in time ascending direction to generate the calculation intervals.

If a negative interval is specified, the interval calculation begins at the latest bounding time in the timeRange and applies the interval repeatedly in time descending direction to generate the calculation intervals. Note that the order of values returned will still be reflected by the timeRange, regardless of the interval sign.

filterExpression
Type: SystemString
A filter expression that follows the performance equation syntax.
includeFilteredValues
Type: SystemBoolean
Specify to indicate that values which fail the filter criteria are present in the returned data at the times where they occurred with a value set to a "Filtered" enumeration value with bad status. Repeated consecutive failures are omitted.

Return Value

Type: AFValues
Returns an AFValues collection with the interpolated values.

Exceptions

ExceptionCondition
PIExceptionError returned by the PI Data Archive.

Remarks

The following table illustrates the interaction between timeRange and interval with the time stamp interval calculations and order of returned values:
Time RangeIntervalTimestamps returned in AFValues
Ascending (Y to T)Positive (5h)Y, Y+5h, Y+10h, Y+15h, Y+20h
Descending (T to Y)Positive (5h)Y+20h, Y+15h, Y+10h, Y+5h, Y
Ascending (Y to T)Negative (-5h)T-20h, T-15h, T-10h, T-5h, T
Descending (T to Y)Negative (-5h)T, T-5h, T-10h, T-15h, T-20h

Note Notes to Callers
This method, property, or class is not available in the legacy .NET 3.5 version of the SDK.

Version Information

AFSDK


See Also

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