Lenze IMSS500+ Simple Servo 500 600 i1000 - Manual (Page 65)

SimpleServo 500/600/i1000 User Manual Rev 3.4
9.7 Tuning in position PVFF mode.
Note
In this mode the settings for Velocity compensation have no effect.
1. Make sure that drive is online (connected).
2. Make sure that the drive is disabled.
3. Set up your indexer (run program for SSi drives) to perform following move:
4. Move forward N steps, where N = number of steps to perform full motor shaft revolution
5. Move backward N steps, where N = number of steps to perform full motor shaft revolution
6. Set acceleration / deceleration to maximum your system allows.
7. Select <Tools> then <Scope> tool from node tree to engage oscilloscope.
8. On the Scope tool select:
9. Motor Velocity as source for Channel 1
10. Position error as source for Channel 2.
11. Timebase: 50mS
12. Trigger: Channel 1, Rising
13. Enable the drive.
14. Select <Compensation> then <Position Loop filter> from node tree. set P-gain to 100 and D –
gain to 200, Vff gain to 1.0, I-gain to 0 and IL limit to 0.
15. Run indexer and observe position error waveform.
16. Slowly increase simultaneously P-gain and D-gain and watch for Position error waveform.
Continue to increase both gains until you see noticeable oscillation on flat portion of
waveform. Now stop increasing P-gain, and continue to increase D-gain until oscillation stops.
Now the ratio between P-gain and D-gain is set and if you need to increase or decrease P-
gain in next steps you will need also increase/decrease D-gain accordingly to keep their ratio.
The task is to minimize position error increasing P-gain and at the same time avoid oscillation
and instability by increasing D-gain. There could be a case when increasing P-gain breaks
system to oscillation and you can even hear audible noise. Increase of D-gain doesn’t fix the
situation. At this point you will need to lower P-gain (and possibly lower D-gain too) to the level
when noise and instabilities disappear.
17. Set up your indexer hereafter, to perform a long move at some arbitrary velocity appropriate
for your system.
18. Observe Position error waveform while running at constant velocity. Look at average Position
error value and change Vff gain to obtain minimum possible velocity error .Generally Vff
value is in range 0.9 - 1.1
19. Set I-gain to 2 Hz and IL to 15%. This is initial setting.
20. Stop indexer and disable drive.
21. Click on <Store gains in EEPROM> to save gains values in drive’s non-volatile memory.
Note
Remember that these are only initial settings for your system. Your application will likely
require fine-tuning. To optimize settings you will need to experiment with combinations of
all gains P,D and I and IL limit settings.
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