Delta RMC101 - Manual (Page 36)

RMC100 and RMCWin User Manual
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• Make a long move without any oscillation or overdrive. Then issue the Set Feed Forward
command. This command will automatically adjust the Feed Forward parameter for the
direction of that move.
• Set the Differential Gain and Integral Gain to zero and keep the Proportional Gain value
from the previous step. Make long slow moves in both directions. Adjust the Extend Feed
Forward and Retract Feed Forward until the axis tracks within 10% in both directions.
In non-regenerating hydraulic systems, the Extend Feed Forward will be less than the Retract
Feed Forward. In regenerating systems, the opposite is true.
5. Readjust the Proportional Gain
Proportional Gain 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.
Slowly increase the gain. When you see a tendency to oscillate as the axis moves or stops,
reduce the gain by 10 to 30 percent.
At this point, if you have gained sufficient control of the system, you may want to increase the
speed, accel and decel of your moves and further adjust the proportional gain. A value of
proportional gain that may seem good at low speeds and accels, may not work at higher speeds.
6. Adjust the Integral Gain
Many hydraulic systems do not require a large Integral Gain. However, it is usually desirable to
have some Integral Gain (5 to 50 units) to help compensate for valve null drift or changes in
system dynamics. Some systems may require larger Integral Gain, in particular if they are moving
a large mass or are nonlinear. Too much Integral Gain will cause oscillations and overshoot. The
Integral Gain is helpful for getting into position and for tracking during long, slow moves. It will not
significantly affect tracking during short, fast moves.
7. Adjust the Acceleration Feed Forwards
The Acceleration Feed Forward terms are particularly useful for systems moving large masses
with relatively small cylinders. Such systems often have a delay before the start of movement.
The Acceleration Feed Forward terms can help compensate for this delay.
Look for following errors during acceleration and deceleration. Increase the Extend and Retract
Acceleration Feed Forward terms until the errors disappear.
For large masses the Acceleration Feed Forward may be in the tens of thousands.
8. Adjust the Differential Gain
Differential Gain may greatly enhance performance on many hydraulic systems. It is used mainly
on systems that have a tendency to oscillate. This happens when heavy loads are moved with
relatively small cylinders. Differential Gain will tend to dampen out oscillations and help the axis
track during acceleration and deceleration. This will positively affect short, fast moves.