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VibrationVIEW Help 23
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use the toolbar button "Settings") and click the Resonance , Extremal or Step Test tabs.
2.3.2 How to enter a Random test
How to enter a Random test
Select the Test...Test Type...Random menu command to switch into Random Test mode .
Select the Test..Define New Test menu command to begin defining a new test. This will guide you
through the following series of configuration dialog boxes. Default values will be supplied for all
parameters. If you are unsure about a parameter, use the default value. After all the values for each
dialog box are entered, click the "Next >" button to advance to the next dialog box. To return to a
previous dialog box, click the "< Back" button.
1. Random Table The amplitude and frequency breakpoints for the test are entered here. Use
the "Insert" and "Delete" buttons to add or remove segments. The small arrow next to the
numbers on the left of the window indicates the current insertion/deletion point.
2. Random Schedule The duration and output amplitude for the test are entered here. Durations
are entered in time, using the format hours:minutes:seconds.
3. Random Parameters The feedback control parameters for the test are entered here. For most
tests the parameters may be left at their default values. In some cases (such as when the control
accelerometer sees a large resonance) these values will need to be
tuned .
4. Random Limits The tolerance and abort limits for the test are entered here. All limits are
measured in dB relative to the demand signal. The tolerance lines are reference lines shown on
the graphs (brown dashed lines) and are used to determine when to switch to "Run" mode when
starting a test. When the number of lines outside the abort limits exceeds the"Max Outlier %", the
test will be aborted. The abort lines are shown on the graphs as solid red lines.
The Max System Gain and Output Threshold parameters are safety limits that depend on your
particular shaker and amplifier. Refer to the "
How to tune Random controller parameters "
section for more information on how to tune these parameters for your system.
The maximum output voltage limit is also entered here. This parameter limits the maximum output
voltage produced by the controller.
5. Random Channels The control channels are selected here, as well as averaging or extremal
channel combination methods.
6. Random Data Storage The directory into which the data from this test will be stored is selected
here. Data can be automatically stored on a regular time interval, at the end of each level (levels
are defined using the
Schedule dialog box) and at the end of the test. Select the check boxes
for your desired data storage times and enter the desired interval times.
At this point the test definition is complete. Click the "Finish" button to close the dialog box. You will be
asked if you want to save the test definition to the hard drive. Click the "Yes" button, enter the desired
name and click the "Save" button to save the test.
To access parameters for specialized tests, select the Test..Edit Test Settings menu command (or
use the toolbar button "Settings") and click the Resonance , Extremal or Step Test tabs.
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