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Chapter 5
Collecting and Reviewing Data
144
4. When finished viewing the spectrum, press Enter to proceed to the next
point in the list.
Keying
Percentage changed
Y-Axis Graph Scaling
Adjustment
Harmonic Markers
Peak cursor
Display Expansion
See
Review Data on page 164
Rockwell Automation Publication 1441-UM001B-EN-P - September 2012
Description
The spectrum displays a percentage changed bar. It provides an overall
value of the current measurement in comparison to alert and danger
alarms. These colored arrows display if the point is in an alarm state
(red), in an alert (yellow) or if there is no alarm (green). If the
measurement amplitude extends beyond the display, an overall
overflow indicator appears at the top of the bar.
This bar displays the percentage of change from the previous overall
reading:
• A positive percentage indicates the measurement is greater than the
previous reading.
• A negative percentage indicates the measurement is less than the
previous reading.
For example, -2% means that the reading is 2% down from the last
reading, or 95% of the last reading; while +2% means that the
reading is 2% up from the last reading, or 102% of the last reading.
• A display of +100% indicates either a 100% increase.
For example, the new reading is twice the old reading, or that there
is either no previous reading, or the previous reading was 0%.
You can use the Up and Down arrows to manually adjust the y-axis
graph scaling on the spectrum. This lets you re-scale the plot to get a
closer look at low amplitude components:
• Up arrow decreases the Y-axis graph scale setting by ½ of its current
setting.
• Down arrow doubles the Y-axis graph scale setting.
The H key displays harmonic markers for the current cursor position.
Harmonic markers rapidly locate integral orders in relation to their
fundamental (1X).
The H key cycles the three harmonic cursor modes:
• Simple, no harmonic cursors.
• Harmonic, displays the harmonics of the current cursor position. The
spectral cursor acts as the fundamental marker, and is re-positioned.
• Fixed, the harmonics remain fixed and cursor can be moved
independently.
The default is Simple (off).
The P key lets you quickly jump the cursor to the next highest peak to
the right of the cursor.
The +/- key graphically expands or compresses the frequency domain
display range horizontally around the cursor position. It reveals
characteristics that may be hidden by the display mode or by the
resolution without changing data collection parameters.
When using +/-, the spectrum's fmax setting expands and the spectrum
reforms to the new fmax. You can repeat to continue to expand up to
the maximum resolution (based on the number of lines of resolution for
the spectrum), after which the function switches to compression.
Dot (.) key immediately toggles the +/- key between display expansion
and compression.
for more information on cursor options.
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