How do aggregated tags work?

The Aggregation Functionality enables you to create smoothed tags, derivatives, etc. by calculating aggregated values over a specified time window.

TrendMiner calculates these aggregations as a 'central moving operator', i.e. it will calculate the operator over a given aggregation level left and right of each point. If you are interested in just looking at the past time interval, you have to shift the aggregated tag by half of the aggregation time.

Available operators are the following:

  • 'Average': Returns the average value within the specified time interval. 
  • 'Minimum': Returns the minimum value within the specified time interval.
  • 'Maximum': Returns the maximum value within the specified time interval.     
  • 'Range': Returns the range between the maximum and minimum value within the specified time interval.
  • 'Delta': Returns the difference between the end and starting value of the specified time interval. This option can be used as an approximation for the derivative tag.
  • 'Integral (/1d)': Calculates the area under the curve over the specified time interval (assuming the tag is expressed in units per day). If the tag on which you base your calculation on has another dimension (eg. tons/hour), you need to take into account a conversion factor (eg. x24 if your tag is in tons/hour) to obtain the correct integral value.