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VibrationVIEW Help 33
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Startup Max System Gain and the Running Max System Gain to 2 times this value.
The Startup Output Threshold parameter is the base output voltage when a test is starting.
The Running Max System Gain is a safety limit that is used to shut down the system when something
goes wrong (e.g. an accelerometer cable falls off). This value typically is the same as the Startup Max
System Gain parameter but may need to be increased if your shaker requires widely varying drive
levels at different frequencies. If a test is incorrectly aborted due to a Max Run System Gain error,
increase this value. The
Running Max System Gain parameter can be determined by running a
sweep through the desired frequency range. After completing one sweep, find the highest output
voltage on a System Gain vs. Frequency graph. Enter 2 times the maximum value for the
Running
Max System Gain parameter.
The Running Max System Output parameter is a safety limit that is also used to shut down the
system when something goes wrong. This parameter typically is double the Startup Max System
Output but may need to be increased if your shaker requires widely varying drive levels at different
frequencies. If a test is incorrectly aborted due to a Max Run Drive error, increase this value. The
maximum output voltage required for a test can be determined by running a single sweep of the test.
After completing one sweep, find the highest output voltage on the Output Drive graph (the cursor
display function may be helpful in finding this value.) Enter 1.5 times the maximum value for the
Running Max System Output parameter.
2.5.2 How to tune Random controller parameters
How to tune Random controller parameters
Click the "Settings" button on the toolbar, or select the Test..Edit Test Settings menu
item.
Click the Parameters tab.
Start with the following values:
Starting Average 3
Starting Gain 0.1
Startup Time 15 sec
Running Average 20
Running Gain 0.05
Slew rate 20 dB/sec
Sample rate Auto
Lines 800
Shutdown rate 60 dB/sec
Clipping6x Sigma
Window type
Blackman
There are two sets of control parameters:
· The Starting parameters are used while the output is ramping up to the control level and generally
have less averaging and a higher gain value because in this mode the system must respond
quickly to equalize the response. A smaller
Starting Gain will increase the time required to reach
the desired output level.
· The Running parameters are used once the output has reached the desired level and generally
have higher averaging and lower gain values than the corresponding Startup parameters because
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