Aggregate List (version 24)
Aggregates
According to the OPC Foundation, aggregates "are methods that summarize data values. Common aggregates include 'average over a given time range', 'minimum over a time range', and 'maximum over a time range'. These aggregates are performed during the retrieval of the data."
The aggregates that Canary supports are defined and maintained by the OPC Foundation. In the list of aggregates, you will notice some have been updated with a second version, represented by the number '2'. These indicate a change in the definition, typically resulting around whether the aggregate uses simple or interpolated bounding values.
Simple Bounding Value - uses the data point immediately before the timestamp to estimate the bounding value if no value exists on the timestamp, even if this point carries a 'Bad' data quality
Interpolated Bounding Value - uses the first non 'Bad' quality data point found before the timestamp to estimate the bounding value if no value exists on the timestamp
With the exception of the Interpolative aggregate which uses Sloped Interpolation to estimate the bounding value, Canary uses Stepped Interpolation to estimate the bounding value for each of its aggregates. See https://reference.opcfoundation.org/Core/Part13/v104/docs/3.1 for more detailed information on how bounding values are calculated and the difference between Sloped and Stepped Interpolation.
The following are the aggregates currently supported by the Canary Excel Add-in and the OPC Foundation. This list can be found within the Excel Add-in ribbon bar within the General info section as well.
| Aggregate Name | Definition |
| Average | Retrieve the average value of the data over the interval. |
| Count | Retrieve the number of raw values over the interval. |
| CountInStateNonZero | Retrieve the number of times a Boolean or numeric was in a non-zero state using Simple Bounding Values. |
| CountInStateZero | Retrieve the number of times a Boolean or numeric was in a zero state using Simple Bounding Values. |
| Delta | Retrieve the difference between the Start and End value in the interval. |
| DeltaBounds | Retrieve the difference between the StartBound and EndBound value in the interval. |
| DeltaTotalCount | Retrieve the total delta of the values for an accumulation tag that resets periodically. |
| DurationBad | Retrieve the total duration of time (milliseconds) in the interval during which the data is Bad. |
| DurationGood | Retrieve the total duration of time (milliseconds) in the interval during which the data is Good. |
| DurationInStateNonZero | Retrieve the time (milliseconds) a Boolean or numeric was in a non-zero state using Simple Bounding Values. |
| DurationInStateZero | Retrieve the time (milliseconds) a Boolean or numeric was in a zero state using Simple Bounding Values. |
| End | Retrieve the last value in the interval. |
| EndBound | Retrieve the value at the end of the interval using Simple Bounding Values. |
| Instant | Retrieve the value at the exact beginning of the interval. |
| Interpolative | At the beginning of each interval, retrieve the calculated value from the data points on either side of the requested timestamp. |
| Maximum | Retrieve the maximum raw value in the interval with the timestamp of the start of the interval. |
| Maximum2 | Retrieve the maximum value in the interval including the Simple Bounding Values. |
| MaximumActualTime | Retrieve the maximum value in the interval and the timestamp of the maximum value. |
| MaximumActualTime2 | Retrieve the maximum value with the actual timestamp including the Simple Bounding Values. |
| Minimum | Retrieve the minimum raw value in the interval with the timestamp of the start of the interval. |
| Minimum2 | Retrieve the minimum value in the interval including the Simple Bounding Values. |
| MinimumActualTime | Retrieve the minimum value in the interval and the timestamp of the minimum value. |
| MinimumActualTime2 | Retrieve the minimum value with the actual timestamp including the Simple Bounding Values. |
| NumberOfTransitions | Retrieve the number of changes between zero and non-zero that a Boolean or numeric value experienced in the interval. |
| PercentBad | Retrieve the percentage of data (0 to 100) in the interval which has Bad StatusCode. |
| PercentGood | Retrieve the percentage of data (0 to 100) in the interval which has Good StatusCode |
| Range | Retrieve the difference between the minimum and maximum value over the interval. |
| Range2 | Retrieve the difference between the Minimum2 and Maximum2 value over the interval. |
| StandardDeviationPopulation | Retrieve the standard deviation for the interval for a complete population (n) which includes Simple Bounding Values. |
| StandardDeviationSample | Retrieve the standard deviation for the interval for a sample of the population (n-1). |
| Start | Retrieve the first value in the interval. |
| StartBound | Retrieve the value at the beginning of the interval using Simple Bounding Values. |
| 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 in seconds) of the data over the interval using Simple Bounding Values. |
| TotalPer24Hours | Retrieve the total (time integral in 24 hours) of the data over the interval using Simple Bounding Values. |
| TotalPerHour | Retrieve the total (time integral in hours) of the data over the interval using Simple Bounding Values. |
| TotalPerMinute | Retrieve the total (time integral in minutes) of the data over the interval using Simple Bounding Values. |
| VariancePopulation | Retrieve the variance for the interval as calculated by the StandardDeviationPopulation which includes Simple Bounding Values. |
| VarianceSample | Retrieve the variance for the interval as calculated by the StandardDeviationSample. |
| 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. |
5 replies
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What unit of measure do the Duration and Time Aggregate values default to?
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