Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 603)

23 • S ETTING UP TRENDS
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X-axis legend
For standard charts, the x-axis legend indicates the time span covered by the trend.
For XY Plot charts, the x-axis legend shows the scale, or range, of values associated with
the selected pen.
The number of timestamps or values shown depends on the size of the trend object and the
number of vertical grid lines.
At run time, you can double-click the x-axis legend, to open the X-Axis tab of the Trend
Properties dialog box. You can set up a trend to exclude the x-axis legend.
Y-axis
The y-axis is the left edge of the chart. It is also known as the vertical axis.
Y-axis legend
The y-axis legend shows the scale, or range, of values for the pens. The minimum and
maximum values for the scale can be:
 Determined automatically (using the best fit for the current data).
 Derived from a pen’s minimum and maximum values.
 Constant values.
 Controlled by tags.
All pens in the trend can use the same scale, or each pen can have its own scale on the y-
axis. When the operator clicks a pen in the line legend, the vertical axis shows the selected
pen’s scale.
For example, if Pen 1 has a minimum value of 10 and a maximum value of 100, the scale
on the vertical axis is 10 to 100 when the pen is selected.
If Pen 2 has a minimum of -10 and a maximum of 50, the scale on the vertical axis
changes to -10 to 50 when the operator selects the next pen in the line legend.
At run time, you can double-click the y-axis legend, to open the Y-Axis tab of the Trend
Properties dialog box. The legend can also be used to pan data. For more information, see
“Panning the trend chart” on page 23-29.
You can set up a trend to exclude the y-axis legend.
Pens
Pens are the lines or symbols used to represent values on a trend chart. The values can be
tags you are monitoring, expressions that manipulate tag values, or constant values.