Tune the speed regulator – Rockwell Automation 23P PowerFlex Digital DC Drive User Manual

Page 108

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108

Rockwell Automation Publication 20P-UM001K-EN-P - July 2014

Chapter 2

Drive Start Up

Tune the Speed Regulator

The speed regulator auto tuning test detects the total inertia value of the motor
shaft (in Kg

m

2

), the friction value (in N

m) and the calculation of the

proportional (P) and integral (I) gains of the speed regulator.

1.

While still in the “Autotune” group, configure the motor shaft rotation
direction via Par 1029 [Speed Tune Dir]; 1 “Forward” = clockwise or 2
“Reverse” = counter-clockwise, with reference to the motor commutator
end.

2.

Speed Regulator Autotune assumes full field is applied. Verify that
parameters 280 [Nom Mtr Fld Amps] and 467 [Max Fld Flux Pct] are
set correctly. Tuning with less than full field current will result in
different gains because of the lower motor torque values.

IMPORTANT

If upgrading a drive to version 6.xxx firmware (from version 5.xxx or earlier)
and it is not possible to perform speed regulator autotuning, see Appendix C,
Manually Tuning the Speed Regulator for Firmware Version 6.xxx on page

301

for instructions on setting the proper gains in the Speed Loop.

IMPORTANT

This test requires the free rotation of the motor shaft combined with the load.
The auto tuning test of the speed loop cannot be carried out on machines with
a limited stroke.

IMPORTANT

If the PowerFlex DC drive is wired for two-wire control, with a digital input
programmed for “Run,” the HIM Start/Stop cannot be used for autotune.
Maintain the “Run” input for autotune.

ATTENTION: The motor will rotate during this tuning procedure. Hazard of
personal injury exists due to motor shaft rotation and/or machinery motion.

IMPORTANT

The test is carried out by using the torque limit value set in the Par 1048
[Autotune Cur Lim] (recommended value = 20%). The torque reference is
applied via a step reference (without a ramp); therefore there must not be any
“backlash” in the mechanical transmission and it must be compatible with
those operations using the torque limit value set in the Par 1048 [Autotune Cur
Lim]. You can modify the torque limit value via this parameter.

IMPORTANT

In applications where the system total inertia value is very high, it is necessary
to increase the value of Par 1048 [Autotune Cur Lim] to avoid “Time out” errors.
The speed regulator auto tuning test of the speed loop is not suitable for drives
used in “elevator” and/or lifting system applications.

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