AF SDK Reference

AFCalculation.CalculateAtIntervals Method

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AFCalculation.CalculateAtIntervals Method

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Last UpdatedNov 18, 2025
2 minute read

This method returns an AFValues collection that contains the result of evaluating the passed expression over the passed time range at a defined interval.

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

Syntax

public static AFValues CalculateAtIntervals(
	Object target,
	string expression,
	AFTimeRange timeRange,
	AFTimeSpan sampleInterval
)

Public Shared Function CalculateAtIntervals ( 
	target As Object,
	expression As String,
	timeRange As AFTimeRange,
	sampleInterval As AFTimeSpan
) As AFValues

Dim target As Object
Dim expression As String
Dim timeRange As AFTimeRange
Dim sampleInterval As AFTimeSpan
Dim returnValue As AFValues

returnValue = AFCalculation.CalculateAtIntervals(target, 
	expression, timeRange, sampleInterval)

public:
static AFValues^ CalculateAtIntervals(
	Object^ target, 
	String^ expression, 
	AFTimeRange timeRange, 
	AFTimeSpan sampleInterval
)

static member CalculateAtIntervals : 
        target : Object * 
        expression : string * 
        timeRange : AFTimeRange * 
        sampleInterval : AFTimeSpan -> AFValues

Parameters

target: Type: SystemObject
The target can either be a PIServer, an AFDatabase, or any derived objects of AFBaseElement. References to attributes or points are based on the target.
expression: Type: SystemString
A string containing the expression to be evaluated. The syntax for the expression generally follows the Performance Equation syntax as described in the PI Data Archive documentation, with the exception that expressions which target elements use attribute names in place of tag names in the equation.
timeRange: Type: OSIsoft.AF.TimeAFTimeRange
The bounding time for the evaluation period.
sampleInterval: Type: OSIsoft.AF.TimeAFTimeSpan
Specifies how often the expression is evaluated.

Return Value

Type: AFValues
Returns an AFValues collection containing the results of the expression calculated at the specified sample interval.

Remarks

Calculations are limited to Attributes or PI Points which originate from a single PI Data Archive. Attributes which resolve to a static value (no data reference configured), are also acceptable.

AF SDK Reference