Delta RMC151 - Manual (Page 49)

2 Starting Up the RMC
2.3.4. Creating Plots for Tuning
To successfully calculate valid gains using the Tuning Wizard - Use Existing Plot method,
you must first generate good plots of motion. The plots should show some motion with
changes. Make sure the plot does not include hitting the end, getting stuck, etc. Make sure the
Output Polarity was correct when the plot was captured, that is, that a positive Control Output
results in movement in the direction of increasing position units.
Plots of motion should:
• Contain significant motion. Slight changes in position, pressure, or force are usually
not enough.
• Contain several changes in position, pressure, or force.
• Include the Control Output and the Actual Position, Actual Pressure, or Actual Force.
• Not include long sections of no motion.
• Contain motion in one direction only. If your position system behaves differently in
each direction of motion, you will need to generate two plots—one for each direction of
motion.
• Be captured at the smallest loop time possible and uploaded in capture mode. Do NOT
use plots captured in trend mode, as they can cause inaccurate results.
Generating Plots
There are two main methods of generating plots of position motion:
• Use Open Loop commands
If your axis is not yet tuned up, use this method. With the Open Loop Rate (10)
command, move the axis and stop it, then upload the plot. You may need to set the
plot duration to be long enough to capture both the start and stop.
• Use Closed-Loop Motion
If your axis is already tuned, you can send closed-loop commands such as Move
Absolute (20), or Enter Pressure/Force Control (Time) (45) to move the axis and
upload a plot.
Even if your axis is not tuned, you can just set the Proportional Gain to achieve some
control of the system and then obtain a plot.
2.3.5. Gain Calculator
The Gain Calculator calculates gains for the axis based on the system model that was
generated by the Tuning Wizard. After the Tuning Wizard completes, the Gain Calculator
opens. Using a simple slider bar, the user can choose gains from conservative to aggressive.
While the Gain Calculator is open, the user can use the Tuning Tools to send move commands
to the axis to try various gains until satisfied.
If the axis has multiple gain sets, the Gain Calculator will apply the gains to the first gain set.
Using the Gain Calculator
Opening the Gain Calculator
In the Plot Manager, in the Tuning Tools, click Gain Calculator. If the axis does not have
a model, you will be prompted to first run the Tuning Wizard. When the wizard completes,
the Gain Calculator will open.
Choosing and Applying Gains
1. Move the slider bar to choose a set of gains. Always start with conservative gains.
2. Click Apply Gains to download the gains to the RMC.
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