Delta RMC101 - Manual (Page 37)

Setup Details 2.2
Starting Up the RMC 2-9
Important: If you use Differential Gain, you may be able to increase the Proportional Gain
somewhat without causing the system to oscillate.
If the drive output during the constant velocity portion of the move is smooth, the Differential Gain
is perhaps not set high enough. The drive output may look "fuzzy." This indicates that the drive is
responding to the minute errors of the axis. Note that not all systems allow the differential gain to
be set high enough for the drive to be "fuzzy".
A disadvantage of Differential Gain is that it amplifies position measurement noise. If there is too
much noise or the gain is too high, this can cause the system to chatter or oscillate.
9. Increase System Speed
Gradually increase the Speed and Acceleration values while making long moves. Look for
following errors, overshoot, or oscillations.
• If an overdrive error occurs, there is not enough drive capacity to drive the axis at the
requested Speed or Acceleration. Should this occur, reduce the Speed and/or Acceleration
and Deceleration.
• If a following error occurs during acceleration and deceleration and adjusting the Gains and
Acceleration Feed Forward does not help, the Acceleration and Deceleration ramps are too
steep for the response of the system.
• If the actual position lags or leads the target position during the entire constant velocity
section of the move, adjust the Feed Forwards.
• Should the system seem a little sloppy, try adjusting the Proportional Gain.
• If the Drive is not high, the gains can probably be increased for better control. If the Drive is
too high, or an overdrive error occurs, the system is not capable of performing the requested
move. The Speed, and/or Accelerations may need to be decreased.
• If the system vibrates while in position, the Dead Band value may need to be increased.
However, if the oscillation is not caused by a deadband in the system then this will not help!
A rule of thumb is to set the Dead Band Eliminator value to half of the peak-to-peak
oscillation of the drive output while in position.
The final tuning of the system should be made at the speed of intended operation.
2.2.3.3 Tuning a Torque Motor
The following procedure may be used to tune motors running in torque mode. Please read the
Tuning Overview before following this procedure.
There is no substitute for experience when tuning an axis. This procedure offers some guidelines,
tips, and suggestions for tuning your system. While these steps will work for some systems, they
may not be the best for a particular system.