Rockwell Automation FactoryTalk Historian SE ProcessBook 3.2 User Guide - Manual (Page 152)

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FactoryTalk Historian ProcessBook User Guide
134
This case plotted 10-minute intervals of two points, A and B, for the last
hour. Point A had 12 point values; Point B had 16 point values. The
number of points plotted equals the number of pairs. Since A had fewer
point values, the plot shows only 12 point pairs. The extra data from point
B is ignored. You can configure the method by which pairing occurs.
Correlation is a measure of the strength of the relationship between two
variables. Correlation is indicated graphically by the spread of the data
points around a fitted straight line (for example, a straight line that
indicates the trend of the data). In general, the closer the points are to the
fitted line, the stronger the correlation. The two FactoryTalk Historian tags
shown in figure 1 are not strongly correlated. Another plot shows perfectly
correlated data:
Perfectly correlated.