Rockwell Automation 999 IMC S Class Compact Motion Controller (Cat. No. 4100-999-122) - Manual (Page 144)

5-64 Understanding IMC-S/23x Setups
Publication 999-122 - January 1997
If this axis is using a velocity loop servo amplifier and the speed implied
by the specified tuning output limit could not be reached in the specified
tuning distance, the message
is displayed. In this case, run the self tuning procedure again specifying
a higher maximum tuning travel or a lower tuning output limit. If
possible, it is best to increase the maximum tuning travel to give the
self tuning more "room" to operate. If this is not possible due to physical
travel constraints on the axis, the tuning output limit must be decreased.
For a velocity loop servo amplifier, the distance traveled during the self
tuning procedure is proportional to the square of the specified tuning
output limit, as shown by the formula below.
This means that if the tuning output limit is cut in half, the axis can be
self tuned in one-quarter of the distance.
After successful completion of the tuning routine, the IMC-S/23x
displays
The total system inertia, measured at a 1V servo output during the test,
is shown in units of milliseconds per count per millisecond (thousand
feedback counts per second, or KCPS).
The damping factor which will be used to compute the loop gains is
also displayed. Initially, the damping factor defaults to 0.8, which
provides good gain values for most systems. Press ENTER to use the
displayed damping factor to calculate the servo gains.
If necessary, the damping factor may be increased to provide additional
damping if required in your application. Raising the damping factor
reduces the amount of overshoot at the end of moves but slows down
the response of the axis. Usually, a damping factor between 0.707 and
2 is sufficient. Damping factors greater than 2 are rarely effective since
the resulting loop gains cause the servo loop to be very sluggish.
*** Insufficient Travel for Tuning:
*** Try Again with Lower Max Output
*** or Higher Max Travel Limit!
*** Gains Not Tuned!
Tuning Travel
α
Tuning Output Limit 2
Tuning Complete!
Damping Factor: 0.8