Rockwell Automation 20P PowerFlex Digital DC Drive - Manual (Page 303)

Rockwell Automation Publication 20P-UM001I-EN-P - February 2013 303
Application Notes Appendix C
8. Start the drive and observe the value of Par 587 [I Reg Err] for a few
seconds, it should settle to a value. Verify that the motor shaft does not
rotate (a small amount of movement, less than a revolution, is OK).
9. Stop the drive.
Note: If a Speed Feedback Loss fault (F91) occurs, increase the value of Par
455 [Spd FB Loss Lvl] to its maximum value.
a.
If Par 587 [I Reg Err] is positive, increase the value of Par 454 [Arm
Inductance]. The magnitude of change is determined by the value of
parameter 587. Generally, make large increases (for example, double)
when Par 587 is large (greater than 40) and smaller increases as Par
587 gets closer to zero.
b. If Par 587 [I Reg Err] is negative, decrease the value of Par 454 [Arm
Inductance]. Again, proportional to the magnitude of Par 587.
10. Repeat step 8 until Par 587 [I Reg Err] is made as close to zero as possible.
Values less than 20 are acceptable as close to zero. However, with some
motors, the minimum value of Par 587 may only be 60 (especially at
smaller current steps). With higher current steps, values can be less than 10
or less than 5.
11. Repeat steps 8 and 9 with Par 39 [Torque Ref ] set to 60% and then again
at 100%. If motor rotation occurs, try lowering the current step value. The
higher the current step, the better the tuning results will be. If motor
rotation still occurs, experiment with trying to set the highest current step
that doesn't cause rotation but is long enough for Par 587 [I Reg Err] to
reach a stable value (typically less than 2 seconds).
12. The current loop should be tuned with the final values of Pars 453 [Arm
Resistance] and 454 [Arm Inductance] and a small value in Par 587 [I Reg
Err].
13. Restore Pars 497 [Field Reg Enable], 469 [Field Mode Sel], 414 [Fdbk
Device Type], 242 [Speed Reg En], 7 [Current Limit], 8 [Current Lim
Pos], 9 [Current Lim Neg], and 455 [Spd FB Loss Lvl] to their original
values.
14. Unlock the motor armature (if necessary).
15. Verify that the motor is attached to any normal application inertia (not
process material) and perform a speed regulator autotune by setting Par
1027 [Spd Reg Autotune] = 1 and pressing the Start button.
16. When autotuning completes, speed regulator tuning values should be
automatically updated.
❏ If the drive is configured as an armature voltage regulator (Par 414
[Fdbk Device Type] = 3 "Armature"), the calculated gains (Pars 87 [Spd
Reg Kp] and 88 [Spd Reg Ki]) may have to be adjusted, because this type
of regulator (voltage) is less responsive than a true speed regulator (that
uses encoder or tachometer feedback).