Rockwell Automation 2711E-ND1 Reference Manual PanelBuilder 1400e - Manual (Page 173)

169 Trends
Publication 2711E-6.15 – November 1998
Note: If the trend contains a large number of values, and the sample
rate is fast, a few unreliable points will be generated while the trend
is re-drawn. These unreliable points may cause a break in the plotted
data, similar to that caused by a communication error. Existing
values are not affected.
If a value is outside the range specified by the Trend Minimum and
Maximum Value controls, the pen line is drawn to the lower or upper
edge of the Trend object and then disappears. When a plotted value
is next within the specified range, a line is drawn from the lower or
upper edge of the Trend object to the new point. No data appears for
the time interval during which the values are outside the specified
range.
Out of Range Plots
Communication Error
If there is an error in the value of the Trend Minimum or Maximum
Value control, the Pen Value label corresponding to the control is
filled with asterisks (***). Values that have already been plotted are
erased, and new data is collected, but not plotted, until the error state
no longer exists. An error state also occurs when the Trend Minimum
Value control value is greater than the Trend Maximum Value control
value, and when there is an overflow or underflow in the value of
either control.
If a communication error occurs, there is a break in the plotted data
until communication is resumed. New values are plotted beginning at
the point in time when communication resumes.
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