Delta RMC151 - Manual (Page 64)

RMC70/150 and RMCTools User Manual
The following procedure may be used to tune a system that uses pressure/force control or
pressure/force limit. This procedure uses pressure/force control, but once an axis is tuned for
pressure/force control, those gains can be used for pressure/force limit with few or no
changes.
Please read the following topics before performing the tuning procedure:
• Tuning Overview
• Tuning a Position Axis
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.
Position/Pressure Tuning Procedure
Pre-Tuning Steps:
These steps come before actually tuning the gains.
1. Set the Pressure/Force Limits
Set the Positive Pressure/Force Limit and Negative Pressure/Force Limit. These specify
the pressure/force range in which the axis will be allowed to control. If the Target
Pressure/Force exceeds these values, an error bit will be set and will halt the axis if the
AutoStops are set to do so.
2. Set the AutoStops
Set the Position Following Error and Pressure/Force Following Error AutoStop to Status
Only to prevent following errors from halting the axis during the tuning. After the tuning
is complete, set the AutoStop to a safe setting for machine operation.
Tuning Steps:
1. Tune the Position Gains
The position gains should be tuned before attempting to tune the axis for pressure/force.
Obtaining control of the axis' position greatly simplifies the tuning of the pressure/force
gains. If you have not yet tuned the position gains, follow the procedure outlined in the
Tuning a Position Axis topic before continuing.
2. Enter Pressure/Force Control
Set the Pressure/Force Proportional Gain to a small value, such as 0.01.
You may wish to move the axis to where it encounters pressure/force before you issue
the Hold Current Pressure/Force (19) command.
Then enter pressure/force control with the Hold Current Pressure/Force (19) command.
Issue the Ramp Pressure/Force (S-Curve) (41) or Ramp Pressure/Force (Linear) (42) or
command to set the Command Pressure to the desired value.
If the axis halts due to an Output Saturated error, reduce the Proportional Gain and
repeat.
3. Adjust the Proportional Gain
Keep increasing the Pressure/Force Proportional Gain until the Actual Pressure/Force
starts moving toward the Target Pressure/Force. It should not get all the way toward to
Target Pressure/Force. Give just enough gain to make sure it is beginning to.
4. Adjust the Integral Gain
Add some Pressure/Force Integral gain, approximately twice as much as the
Pressure/Force Proportional Gain. The Actual Pressure/Force should go towards the Target
Pressure/Force.
44 Delta Computer Systems, Inc.