Comparing Classic Historian Data Plots and Historian Plots

If you compare plots of average, minimum, and maximum data in Classic Historian with similar plots in Historian, you may notice the following differences:

• The sample pens match, but the plot of the average value differs. Classic Historian computes the average during the ?next ? period and Historian computes the average over the ?previous ? period.
• Classic Historian also records the minimum/maximum value from raw data values, whereas Historian uses interpolated values to compute the minimum/maximum value.
• Historian uses interpolated value because Historian works with compressed data. When you work with compressed data, interpolated values let you project what the likely minimum/maximum values were during a given time interval that includes few raw data values due to compression.