Rockwell Automation 9301 Series RSView32 Users Guide - Manual (Page 484)

Configuring trends
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13–13
Digits
Select the number of characters you want to display in the pen scale,
including the decimal point. The values that appear in the scale are
selected in the Pen Configuration tab. Specify enough digits so the
scale is wide enough to display the minimum and maximum values for
all your tags. If the pen value does not fit it appears in scientific
notation.
To display the division markings on the vertical axis without numbers,
select 0.
Grid
Check this box to have horizontal grid lines extend from the major
and minor divisions on the vertical axis.
Choosing a data source
The data for trends can be real-time, historical, or file–based. Real-
time data comes from the value table. Historical data comes from a
data log model’s set of files. File–based data comes from a single log
file at a time.
For a real-time trend:
Click the Real Time button.
The buffer for each real-time trend pen can contain up to 2,000 tag
values. A tag value is saved to the buffer whenever that value changes.
When the buffer is full, the oldest value is overwritten with a new
value.
To ensure a real-time trend contains data, see “Ensuring real-time
trends have data” on page 13-26.