This Object is used as the browse entry point for information about the Aggregates supported by a Server. The content of this Object is already defined by its type definition. All Instances of the FolderType use the standard BrowseName of ‘AggregateFunctions’. The HasComponent Reference is used to relate a ServerCapabilities Object and/or any HistoricalServerCapabilities Object to an AggregateFunction Object. AggregateFunctions is formally defined in Table 3.
Table 3 – Aggregate Functions Definition
Attribute 
Value 

BrowseName 
AggregateFunctions 

References 
Node Class 
BrowseName 
DataType 
TypeDefinition 
ModellingRule 

HasTypeDefinition 
Object Type 
Defined in OPC 100005 
Each ServerCapabilities and HistoricalServerCapabilities Object shall reference an AggregateFunction Object. In addition, each HistoricalConfiguration Object belonging to a HistoricalDataNode may reference an AggregateFunction Object using the HasComponent Reference.
This ObjectType defines an Aggregate supported by a UA Server. This Object is formally defined in Table 4.
Table 4 – AggregateFunctionType Definition
Attribute 
Value 

BrowseName 
AggregateFunctionType 

IsAbstract 
False 

References 
Node Class 
BrowseName 
DataType 
TypeDefinition 
Mod.Rule 
Subtype of the BaseObjectType defined in OPC 100005 
For the AggregateFunctionType, the Description Attribute (inherited from the Base NodeClass), is mandatory. The Description Attribute provides a localized description of the Aggregate.
Table 5 specifies the BrowseName and Description Attributes for the standard Aggregate Objects. The description is the localized “en” text. For other locales it shall be translated.
Table 5 – Standard AggregateType Nodes
BrowseName 
Description 

Interpolation Aggregate 
Interpolative 
At the beginning of each interval, retrieve the calculated value from the data points on either side of the requested timestamp. 
Average 
Retrieve the average value of the data over the interval. 
TimeAverage 
Retrieve the time weighted average data over the interval using Interpolated Bounding Values. 
TimeAverage2 
Retrieve the time weighted average data over the interval using Simple Bounding Values. 
Total 
Retrieve the total (time integral) of the data over the interval using Interpolated Bounding Values. 
Total2 
Retrieve the total (time integral) of the data over the interval using Simple Bounding Values. 
Minimum 
Retrieve the minimum raw value in the interval with the timestamp of the start of the interval. 
Maximum 
Retrieve the maximum raw value in the interval with the timestamp of the start of the interval. 
MinimumActualTime 
Retrieve the minimum value in the interval and the timestamp of the minimum value. 
MaximumActualTime 
Retrieve the maximum value in the interval and the timestamp of the maximum value. 
Range 
Retrieve the difference between the minimum and maximum value over the interval. 
Minimum2 
Retrieve the minimum value in the interval including the Simple Bounding Values. 
Maximum2 
Retrieve the maximum value in the interval including the Simple Bounding Values. 
MinimumActualTime2 
Retrieve the minimum value with the actual timestamp including the Simple Bounding Values. 
MaximumActualTime2 
Retrieve the maximum value with the actual timestamp including the Simple Bounding Values. 
Range2 
Retrieve the difference between the Minimum2 and Maximum2 value over the interval. 
Count 
Retrieve the number of raw values over the interval. 
DurationInStateZero 
Retrieve the time a Boolean or numeric was in a zero state using Simple Bounding Values. 
DurationInStateNonZero 
Retrieve the time a Boolean or numeric was in a nonzero state using Simple Bounding Values. 
NumberOfTransitions 
Retrieve the number of changes between zero and nonzero that a Boolean or numeric value experienced in the interval. 
Start 
Retrieve the value at the beginning of the interval. 
End 
Retrieve the value at the end of the interval. 
Delta 
Retrieve the difference between the Start and End value in the interval. 
StartBound 
Retrieve the value at the beginning of the interval using Simple Bounding Values. 
EndBound 
Retrieve the value at the end of the interval using Simple Bounding Values. 
DeltaBounds 
Retrieve the difference between the StartBound and EndBound value in the interval using Simple Bounding Values. 
DurationGood 
Retrieve the total duration of time in the interval during which the data is Good. 
DurationBad 
Retrieve the total duration of time in the interval during which the data is Bad. 
PercentGood 
Retrieve the percentage of data (0 to 100) in the interval which has Good StatusCode. 
PercentBad 
Retrieve the percentage of data (0 to 100) in the interval which has Bad StatusCode. 
WorstQuality 
Retrieve the worst StatusCode of data in the interval. 
WorstQuality2 
Retrieve the worst StatusCode of data in the interval including the Simple Bounding Values. 
AnnotationCount 
Retrieve the number of Annotations in the interval (applies to Historical Aggregates only). 
StandardDeviationSample 
Retrieve the standard deviation for the interval for a sample of the population (n1). 
VarianceSample 
Retrieve the variance for the interval as calculated by the StandardDeviationSample. 
StandardDeviation Population 
Retrieve the standard deviation for the interval for a complete population (n) which includes Simple Bounding Values. 
VariancePopulation 
Retrieve the variance for the interval as calculated by the StandardDeviationPopulation which includes Simple Bounding Values. 