Tuning the position loop, Velocity loop tuning examples – Rockwell Automation 1398-DDM-xxx ULTRA 100 Series Drives Installation Manual User Manual

Page 175

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Publication 1398-5.2 – PDF 1997

Tuning

9-9

Tuning the Position Loop

Specify the step period and step position values, and then input a
square wave to the position loop. Adjust the gain parameters Kp, Kd,
Kff, Ki, and Ki Zone to tune the system.

1. Disable the drive.

2. Choose

Manual Tune (Position Step)

from the tuning window.

3. Enter an appropriate

Distan

c

e count

(step position) for the inter-

nal square wave.

4. Enter an appropriate time to complete one cycle of the square

wave for the internal step position.

5. Select the desired Motor Direction (

B

iDirectional

,

For

w

ard Only

or

R

e

verse Only

).

6. Select the

Osci

l

loscope

.

7. Enable the drive.

8. Choose

S

tart

. The motor will move and the oscilloscope will dis-

play the commanded position and motor position.

9. Increase the

K

p

gain while monitoring the signal on the scope.

The Kp gain should be adjusted until the desired rise time is
achieved, with no overshoot. Refer to Figure 9.3.

10. Increase

K

i

very slowly until the signal begins to overshoot.

11. Increase

K

d

very slowly to remove the overshoot caused by Ki.

12. In general you may leave the

K

ff

gain set to 100.

13. Choose

S

top

.

14. Disable the drive.

15. Choose

N

ormal Drive Operation

.

16. Choose

C

lose

.

17. Enable the drive.

The position loop has been tuned. The drive may be operated as a
master encoder, step/direction or step up/down configuration.

Velocity Loop Tuning Examples

Note: Tune the velocity loop before attempting to tune the position
loop. The bandwidth of the velocity loop must be set before position
loop tuning is attempted.

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