Delta RMC101 - Manual (Page 56)

Appendix B: Tuning RMC100 Startup Guide
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4. Add Filter if Necessary
If the pressure feedback signal is excessively noisy, it may cause instability and
will likely have been noticed already in the previous step. Adding a filter may
help. This is done using the Filter TC parameter. See Filter TC for detailed
information.
5. Adjust the Integral Gain
The Integral Gain helps get to the command pressure quickly.
• Use the same Event Step sequence as previously to ramp between two
pressures. You may want to increase the delay between the steps to more
clearly see the effect of this tuning step.
• Adjust the Integral Gain so that the pressure gets to commanded pressure
quickly.
• Too much Integral Gain will cause oscillations and overshoot. If this
happens, decrease the Integral Gain.
6. Adjust the Differential Gain
Differential Gain greatly enhances performance on many hydraulic systems.
Differential Gain will tend to dampen out oscillations and help the axis track
during acceleration and deceleration. This will positively affect short, fast
moves.
• Continue ramping between two pressures.
• If the drive output is always smooth, the Differential Gain can probably be
increased. The drive output should look "fuzzy." This indicates that the
drive is correctly responding to the minute errors of the axis.
• A disadvantage of Differential Gain is that it amplifies measurement noise.
If there is too much noise or the gain is too high, this can cause the system
to chatter or oscillate. In this case, decrease the Differential Gain.
7. Readjust the Proportional Gain
Once the Differential Gain has been adjusted, the Proportional Gain may be
readjusted. It affects the responsiveness of the system. Low gains make the
system sluggish and unresponsive. Gains that are too high make the axis
oscillate or vibrate.
• Continue ramping between two pressures.
• Slowly increase the gain. When you see a tendency to oscillate as the
pressure changes or stops, reduce the gain by 10 to 30 percent.
8. Tune the Transition.
Now that both the position and pressure gains have been tuned, the transition
may be tuned.
• Use the Event Step sequence to transition from position to pressure.
• If necessary, adjust the previously tuned pressure parameters for a
smoother transition.
• If there is oscillation and overshoot or other undesirable behavior at the
transition that cannot be avoided with tuning the gains, the Ramp Time
may need to be changed, or the speed going into the transition may be need
to be slower.