Rockwell Automation 57C422B 2 Axis Servo Module - Manual (Page 58)

4-30 2-Axis Servo Module M/N 57C422B
The self-tuning of an axis should always be done in the
following order:
1. Tune gains
2. Tune dynamics (if required by application)
3. Tune feedforward gain (if required by application)
The tune gains command is used to initiate self-tuning of the
control loop gains. The module will tune the gains in the
following order:
1. Deadband Compensation
2. Velocity Gain
3. Integral Gain
4. Proportional Gain
The tune gains command results in movement of the axis in
both directions. Registers 17, 18 are used to define the
tuning increment i.e., the distance that the axis will move
while attempting to auto-tune. This increment is typically
between .25 and .5 revolutions of the motor shaft.
The results obtained from the "tune gains" command are
stored in registers 3, 4, 5, and 7.
The tune dynamics command will determine the maximum
velocity and accel and decel limits for the servo system
(motor and drive). Register 8 is used to define the maximum
allowable following error. Registers 11, 12 are used to define
the allowable travel distance, and registers 19 through 24 are
used to limit the accel, decel and velocity. The feedback
encoder should be in "linear" mode while this function is
being performed. If there are no machine limitations, these
registers may be set to any large value. In order for this
command to work properly, the motor must be able to rotate
in both directions for many revolutions. If this is not possible,
this command should not be used.
The results obtained from the tune dynamics command are
stored in registers 19 through 24. These values represent the
maximum values achievable with minimum following error.
You can exceed these values if you are not concerned with
the amount of following error or you can use a lower value if
your application requires ft.