Rockwell Automation 1398-DDM-xxx USE MNL/ULTRA 200 DIG.SERVO.DR - Manual (Page 174)

Publication 1398-5.0 – October 1998
9-4 Tuning
Auto Tune Mode
The Auto Tune mode uses a “self-tuning” algorithm that
automatically adjusts the drive’s velocity loop gain parameters.
Adjustments do not require special equipment. This mode will tune a
drive for constant velocity loop response across different applications.
The results will often provide acceptable response but in general
should be considered a starting point.
Tuning parameters adjustments are set to achieve a reasonable
bandwidth and servo response based on the system inertia and
friction. Auto tune may be used when a significant amount of
compliance or backlash exists (for example, belt systems) in the
mechanical load, but precise tuning requires the load be fully coupled
to the motor. Instability problems occur when the load is not fully
coupled to the motor.
Auto Tuning
A PC running ULTRA Master is required to perform tuning on a
ULTRA 200 Series drive. The optional TouchPad does not support
tuning.
Before auto tuning is invoked, three autotuning parameters must be
set:
●
Distance sets the rotation limit of the motor. This is the maximum
distance the motor is allowed to move during any one test. (Note:
a test in the bi-directional mode includes two different tests.)
●
Step Current sets the amount of current given to the motor during
the test. If this is set too low, a system may not move enough to
gather sufficient data, if it is set too high the test will be too short
and very jerky.
●
Motor Direction (Forward Only/Reverse Only/Bi-directional) sets
the rotational direction for the test. The bi-directional test does the
same test in both directions, with the forward rotation first.
Auto tune procedures are explained for each drive configuration in
“Application and Configuration Examples” starting on page 8-1. The
following steps generalize these procedures.
When autotuning is selected, the drive rotates the motor shaft for a
short time interval, typically a few seconds. Motor movement should
not exceed 30 seconds.
Note: The autotune algorithm will not provide satisfactory results in
systems with significant gravitational effects.
!
Intro
ATTENTION: Rotating motor shafts can cause extensive
damage and injury. Motors must be properly guarded dur-
ing testing and installation.