Rockwell Automation 20G PowerFlex 750-Series AC Drives - Manual (Page 367)

Rockwell Automation Publication 750-RM002B-EN-P - September 2013 367
Integrated Motion on the EtherNet/IP Network Applications for PowerFlex 755 AC Drives Chapter 6
Loop Response: The Loop Response attribute is used to determine the
responsiveness of the control loops. Specifically, the Loop Response attribute is
used to determine the value for the Damping Factor (Z) used in calculating
individual gain values:
• High = 0.8
• Medium = 1.0
• Low = 1.5
Load Coupling: The Load Coupling attribute is used to determine how the loop
gains are de-rated based on the Load Ratio.
In high performance applications with relatively low Load Ratio values or rigid
mechanics, typically Rigid is selected. The gains are not de-rated.
For applications with relatively high Load Ratios and compliant mechanics,
Compliant is selected. The autotune algorithm divides the nominal loop
bandwidth values by a factor of the Load Ratio + 1.
Measure Inertia using Tune Profile: Check this box to calculate the inertia
tuned values as part of the autotune. The Inertia Test results are shown in the
Inertia Tuned grid control (bottom right of the dialog box) when the test
completes.
When Measure Inertia using Tune Profile is selected as a part of the Autotune
test, the PowerFlex 755 drive first jogs or rotates the motor in a single direction to
remove any backlash present in the system (as depicted in the chart below). After
the backlash has been removed, the “bump” profile is then applied to measure the
system inertia (system acceleration). Note that systems with a mechanical
restriction or travel limit may not complete the Autotune test.
Profile to Measure Inertia
Backlash Removal