Emerson FM-3 - Manual (Page 71)

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Setting Up Parameters
value higher than the actual inertia, the resultant motor response will tend to be more
oscillatory.
Friction
This parameter is characterized in terms of the rate of friction increase per 100 motor RPM.
If estimated, always use a conservative (less than or equal to actual) estimate. If the friction
is completely unknown, a value of zero should be used. A typical value used here is less than
one percent.
Low Pass Filter Group
The Low Pass Filter will reduce machine resonance due to mechanical coupling and other
flexible drive/load components by filtering the command generated by the velocity loop.
Low Pass Filter Enable Checkbox
When selected it enables a Low Pass Filter to be applied to the output of the velocity
command before the torque compensator.
Low Pass Frequency
This parameter defines the Low Pass Filter cut-off frequency. Signals exceeding this
frequency will be filtered at a rate of 40 dB per decade. The default value is 600Hz.
Tuning Group
Response
The Response adjusts the velocity loop bandwidth with a range of 1 to 500 Hertz. In general,
it affects how quickly the drive will respond to commands, load disturbances and velocity
corrections. A good value to start with (the default) is 50 Hz. The maximum value
recommended is 80 Hz.
Enable Feedforwards Check Box
When feedforwards are enabled, the accuracy of the Inertia and Friction parameters is very
important. If the Inertia parameter is larger than the actual inertia, the result could be a
significant overshoot during ramping. If the Inertia parameter is smaller than the actual
inertia, following error during ramping will be reduced but not eliminated. If the Friction
parameter is greater than the actual friction, it may result in velocity error or instability. If the
Friction parameter is less than the actual friction, velocity error will be reduced but not
eliminated.
Position Error Integral Group
Time Constant Check Box
This enables the Time Constant parameter.