The Tuner Tool

Description

The Tuner tool is used for tuning feedback loops on Galil motion controllers and PLCs. It allows easy access to the available filter, provides for test signals to evaluate the current filter, and includes auto-tuning algorithms for various applications.

The Tuner showing the basic filter for axis A of a DMC-4020.

Safety while Tuning

An improperly tuned feedback loop can result in instability and other undesirable motion or plant behavior.

Click the stop button on the Tuner tool to send AB;MO to disable the feedback loop.

Working with Galil's filter

Upon connection, the tuner provides a chooser to select the axis (or PLC feedback loop channel) for the hardware. Choose the axis desired to automatically populate the filter interface.

The tuner is laid out as a toolbox view of multiple items. Each item marked with a filter icon contains settings for the filter. Each setting has an interface element, such as a slider, that allows the user to set the parameter as needed. The user may also type directly into text fields and spin boxes to set the filter via the keyboard.

A filter panel showing the Pole and Notch filter.

Filter panels are live. User input is transmitted directly to the controller. If the setting is changed via another source, e.g. an auto-tuner, the panel will update real time.

Test Signals

Depending upon the needs for tuning, some sort of test signal is usually employed to judge the performance of the filter. This may be a user's program, a profiled move entered into the Terminal, a motion generated by an external software application, or other test movement.

The GDK Tuner includes test signals to aid in tuning evaluation.

Open the Test Signals panel to view the available test signals for the current connection. Modify the test signal as needed and click the Send Test Signal button at the bottom of the Tuner tool to initiate the test. The button will switch to an inactive status until the test is complete.

To aid in tuning, the tool can automatically send the specified test signal every 5 seconds while tuning parameters are adjusted on the fly. Click the Repeat Test Signal button at the bottom of the tool to toggle the auto-repeat function.

The Profiled Move test signal panel.

Autotuning Algorithms

Tuning can often be greatly simplified by using one of Galil's autotuning algorithms.

GDK's Tuner tool ships with autotuning algorithms to aid in quick tuning.

Open the Tuning Algorithms panel to view the available algorithms for the current connection. Modify the algorithm properties as needed and click the Run Autotuner button at the bottom of the Tuner tool to initiate the test. The button will switch to an inactive status until the algorithm is complete.

After the algorithm completes, the currently selected Test Signal will automatically be sent.

Advanced Tuning

See Step-By-Step servo tuning with the Tuner and Scope for a walk-through of tuning techniques.