AFCalculation.PercentTrue Method

public static AFValues PercentTrue(
	Object target,
	string expression,
	AFTimeRange timeRange,
	AFTimeSpan calculationInterval,
	AFTimeSpan minimumSampleInterval,
	AFTimestampCalculation timeType,
	out AFValues percentGood
)

Public Shared Function PercentTrue ( 
	target As Object,
	expression As String,
	timeRange As AFTimeRange,
	calculationInterval As AFTimeSpan,
	minimumSampleInterval As AFTimeSpan,
	timeType As AFTimestampCalculation,
	<OutAttribute> ByRef percentGood As AFValues
) As AFValues

Dim target As Object
Dim expression As String
Dim timeRange As AFTimeRange
Dim calculationInterval As AFTimeSpan
Dim minimumSampleInterval As AFTimeSpan
Dim timeType As AFTimestampCalculation
Dim percentGood As AFValues
Dim returnValue As AFValues

returnValue = AFCalculation.PercentTrue(target, 
	expression, timeRange, calculationInterval, 
	minimumSampleInterval, timeType, 
	percentGood)

public:
static AFValues^ PercentTrue(
	Object^ target, 
	String^ expression, 
	AFTimeRange timeRange, 
	AFTimeSpan calculationInterval, 
	AFTimeSpan minimumSampleInterval, 
	AFTimestampCalculation timeType, 
	[OutAttribute] AFValues^% percentGood
)

static member PercentTrue : 
        target : Object * 
        expression : string * 
        timeRange : AFTimeRange * 
        calculationInterval : AFTimeSpan * 
        minimumSampleInterval : AFTimeSpan * 
        timeType : AFTimestampCalculation * 
        percentGood : AFValues byref -> 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 within the expression are based on the target.

expression

Type: SystemString
A string containing the boolean 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.

calculationInterval

Type: OSIsoft.AF.TimeAFTimeSpan
The length of the calculation interval. A value will be returned for each interval within the specified time range.

minimumSampleInterval

Type: OSIsoft.AF.TimeAFTimeSpan
Specifies the minimum sample time within each interval to evaluate the expression at. A smaller sample time will provide a more accurate answer at the cost of longer execution time and heavier PI Data Archive load.

timeType

Type: OSIsoft.AF.DataAFTimestampCalculation
A flag indicating what how to calculate a timestamp for each interval.

percentGood

Type: OSIsoft.AF.AssetAFValues
Out parameter indicating the percent good of each calculation interval value.

Return Value

The caller can also control how often the expression is evaluated during the computation of the Percent True results with the MinSampleInterval argument. The server will limit the MinSampleInterval to between 1/100 and 1/10000 of the calculation period. This flexibility allows the user to manage the trade-off between accuracy and execution time. Higher accuracy typically imposes a heavier load on the server. In the extreme cases, this may impact other applications from accessing the server.

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.

AFSDK

Reference