Servo tuning with the tuner and scope

Getting Started

The purpose of this exercise is to provide a basic guide to tuning with the GDK Tuner Tool using the GDK Scope for analysis. The following are the required components to perform this exercise.

  1. GDK supported Galil controller.
  2. Motor Amplifier.
  3. Commutated Motor.
  4. A computer running the latest version of GDK software.
  5. A GDK Pro license.

The following steps will cause motion on the selected axis. If the motor goes unstable, click the stop button on the Tuner tool to send AB;MO to disable the feedback loop.

Connect to the Controller

  1. To connect the Scope and Tuner to the desired controller, first make sure that the correct address is aliased in the GDK Manager.
  2. Open the Scope and the Tuner by clicking their respective icons in the GDK Manager toolbar.
  3. The tools should automatically connect to the controller selected in step 1.
  4. Dock the Scope to the top so that the Scope and Tuner can be viewed simultaneously. To do this, click the docking icon in the Scope and click Dock Top or use the key combination Alt + Up Arrow.
  5. To tune axis A, click on the A-axis in the Axis Selector drop down menu in the Tuner.
The controller is now connected to the Scope and Tuner and the A-axis is selected.

Selecting Scope Channels

  1. Type RP in the Data Record tab of the Scope to search for the Reference Position channel. Double click on _RPA.
  2. Type TP and double click on _TPA.
  3. Type TE and double click on _TEA.
  4. Type TT and double click on _TTA.
Four Scope channels added.

Set Scope Scale

  1. In the Tuner tool, click on Test Signal and verify that the Step Input signal is selected.
  2. Click the Send Test Signalbutton.
  3. Click the Zoom into waveform extentsbutton in the Scope.
  4. In the Channels tab of the channel sidebar (shown above), select rows _RPA, _TPA, and _TEA.
  5. Click the icon next to the Scale column header and set all three scales to 50.0.
  6. Select only rows _RPA, and _TPA.
  7. Click the icon next to the Offset column header and set all both offsets to 2.0.
  8. Set the scale of _TTA to 5.0 in its scale cell.
Scales and Offsets set.

Set Scope Trigger

  1. Set the Trigger Mode to Normal and set the Scope trigger to _RPA
  2. Set the Trigger Level to 50.0
  3. Set the Trigger Edge to rising /.
Trigger settings.

Run the Tuner

  1. In the Tuner tool, click on Tuning Algorithms and verify that the Auto-Crossover signal is selected.
  2. Click the Run Autotuner button.
  3. The Autotuner will run through Galil's Auto-Crossover tuning algorithm and a Test Signal will be sent.
The test signal response after the Auto-Crossover algorithm.

Conclusion

The steps above show how an application can be quickly and easily tuned. The parameters set by the Autotuner will be sufficient for most applications. In some cases, additional manual or fine tuning will be required.