Rockwell Automation 8720MC Drives Integration Manual - Manual (Page 42)

Publication 8720MC-IN002A-EN-P — December 2002
2-10 Commissioning Your 8720MC Analog Drive
For the analog configuration, auto tuning will automatically calculate
the following Group 0 Servo Loop parameters: Parameter 100, “Vel
Prop Gain 0”; Parameter 101, “Vel Integ Time 0”; Parameter 523,
“System Accel 0”; Parameter 562, “Torq Lowpas Frq0” and “Pos Loop
Gain 0”.
Before initiating the auto tune procedure, ensure that the Parameter
546, “Atune Config”, has the four lowest significant bits set to one.
This means that:
• bit 0 - “Auto Save” is on and the calculated parameters will be
automatically saved
• bit 1 - “Calc Gains” is on and the proportional and integral gains
for the selected servo loop parameter group will be calculated
• bit 2 - “Inertia” is on and the system acceleration for the selected
servo loop parameter group will be calculated
• bit 3 - “Auto Offset” is on and the system calculates the analog auto
reference offset, parameter 693.
The speed for the auto tune procedure as well as the torque and the
maximum distance for the auto tune moves can be modified.
Parameter 543, “ATune Vel Limit”; Parameter 542, “ATune Torq Limit”
and Parameter 544, “ATune Posn Limit” serve this purpose. The
default values are 1000 RPM, 100% rated continuous torque and
65,535 counts, respectively. Changing these values will change the
calculated values of the servo loop parameters. The default values
represent a good compromise and should be used unless the
application does not support the default values. For example, if you
know the torque will be limited to 75% of rated motor torque,
Parameter 542 should be set to 75%.
To Auto tune the drive:
1. With the drive disabled set parameter 541 to “Execute”.
2. Making sure the motor and load are safe to operate, enable the
drive. The motor will quickly rotate clockwise and
counter-clockwise indicating that the auto tune procedure has
executed. Parameter 547 will indicate “successful” if the auto tune
procedure executed properly.
3. Disable the drive and set parameter 541 to “Idle”.