Rockwell Automation 1441-PEN25-Z Enpac 2500 Data Collector - Manual (Page 133)

Rockwell Automation Publication GMSI10-UM002D-EN-E - August 2012 133
Collecting and Reviewing Data Chapter 4
See Review Data on page 153 for more information on cursor options.
Table 34 - Spectrum Keying Descriptions
Keying Description
Percentage changed 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%.
Y-Axis Graph Scaling
Adjustment 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.
Harmonic Markers 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).
Peak cursor The P key lets you quickly jump the cursor to the next highest peak to the right of the
cursor.
Display Expansion 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 spectrums 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.