CNC Setup Utility Manual
P/N 70000490C - Tuning the Current, Velocity, and Position Controller
5-2
All rights reserved. Subject to change without notice.
10-December-04
Current Controller Auto-tuning Test
The system provides an auto-tuning feature for the current controller.
The velocity and position loops are open (that is, switched off) for this
test.
To auto-tune the current controller
1. On the Software Options menu, select
Motion Setup/Testing
(MST)
(option 3) and press
ENTER
.
2. Press
TuneMod
(
F6
). Select
Automatic
and press
ENTER
.
3. On the MST screen, select an axis [
X
,
Y
,
Z
,
U
, or
S
(spindle)]. This
activates the axis.
4. Press
Tuning
(
F7
) to display a pop-up menu with the tuning mode
tests. Select
Current Tune
and press
ENTER
.
The test loads a new proportional gain value on each test iteration (it
is increased by 1000). No initial parameter is needed. The initial gain
is started at 1000, and is incremented until it produces an over-
damped response. The feedback and setpoint current are stored and
analyzed. While the test is running, the test window displays the
loaded current proportional gain and the calculated compensation
time. See
Figure 5-1, Current Auto-tune Plot
5. The test is stopped with an optimal proportional gain. That is, when
the step response compensation time t
aus
is less than 600
µ
sec.
When the test stops, the display shows a message at top of the
screen, and the optimal value is displayed at bottom of the screen.
Another message asks, “Do you want to save the new parameter(s)?”
6. Press
Yes
(
F1
) to load and store the displayed test value in the
configuration file. Press
No
(
F2
) to load and store the current value.
7. Repeat Steps 1–6 for each axis [
X
,
Y
,
Z
,
U
, or
S
(spindle)]. Then
perform the Frequency Auto-tuning Test.
NOTE:
Cycle
E
-
STOP
after each Current test.
Selecting
Yes
in Step 6 changes the following Machine Constants
(depending on the axis selected):
MC_2020: X Current Control Gain N<Nom (mV/A)
MC_2120: Y Current Control Gain N<Nom (mV/A)
MC_2220: Z Current Control Gain N<Nom (mV/A)
MC_2320: U Current Control Gain N<Nom (mV/A)
MC_2920: Spindle Current Control Gain N<Nom (mV/A)
