Delta RMC101 - Manual (Page 38)

RMC100 and RMCWin User Manual
2-10
Tuning Procedure
1. Do Open Loop Move
This step is for verifying that the system wiring and setup is correct before doing any closed loop
control. Issue an Open Loop (O) command with a small drive, such as 50-150. Increase the drive
until the axis begins to move. A positive drive should yield increasing counts. Issue an Open Loop
command again with a negative drive. This should yield negative counts.
Before continuing, verify that all the Gains and Feed Forwards are set to zero.
2. Check Dead Band
If your system has a large dead band, you will need to set the Dead Band Eliminator value. To
find your dead band, give increasing amounts of drive to the system with the Open Loop
command. The value of drive at which the system starts to move is your dead band. If this value
is approximately 400 or greater, the Dead Band Eliminator should probably be used. If it is less, it
is left to the discretion of the designer.
3. Adjust the Differential Gain
Torque motors generally do not have much damping. Damping must be provided for the system,
or it will be difficult to control. Providing some Differential Gain will effectively dampen the system.
Do the following:
a. Set all the gains to zero. Issue an Open Loop (O) command of zero.
b. Increase the Differential Gain. Issue a Set Parameters (P) command to put the axis in
closed loop control.
c. Repeat b until sufficient damping is obtained. There are several methods this can be done,
depending on the system:
• For small motors, rotate the motor manually to get a feel for the resistance to movement
(damping). Repeat step b until the damping is significant. If the motor chatters or
oscillates, decrease the gain.
• For systems that cannot be moved manually, repeat step b until the motor starts
humming (or chattering or oscillating) and then back the Differential Gain off
significantly, perhaps even 50%, to avoid oscillating later while making moves.
• For finer adjustment on large systems, repeat step b, and then momentarily (e.g. 5
milliseconds) give a drive output to the motor. The event step table can be used to do
this with the Open Loop command. This jolt to the system will provide a clear indication
of whether the Differential Gain is too high.
Do not set the Differential Gain too high! Remember that the point here is only to provide
some damping for continuing the tuning process. The Differential Gain will be fine-tuned later.
Keep in mind that motors often require a very high Differential Gain.
4. Adjust the Proportional Gain
Adding Proportional Gain will now improve system performance. Adjust the Proportional Gain by