Rockwell Automation Publication 750-AT006D-EN-P - January 2022 76
Chapter 5
Manual Tuning
This chapter provides a common method of manually tuning a drive. It is often referred to as inside-out tuning, where the inner current loop
is tuned, then the velocity loop is tuned, followed by the outer position loop if the drive is in Position mode. It involves incremental increases
in control loop gains to the point of marginal stability, then backing them off by a given percentage. Typical ranges for various gains are also
given to provide guidelines.
The out-of-box and autotune rigid methods achieve relatively high performance. However, if you are comfortable with tuning, this method
can help to improve performance from autotune compliant settings or if maximum performance is required. The method can be used in the
following situations where previously described methods do not produce the required level of performance:
• To improve performance starting with out-of-box or autotune settings
• To tune a difficult load from a stable initial state
Other requirements include the following:
• Start with a set of gains that produces stable operation
• The load is connected to the motor while tuning
This chapter also includes information about how to manually tune the drive in Encoderless Mode. The drive operates in Encoderless Mode
when 1, 2, and 3 are all true:
1. The drive is set to Induction FV (0:65 [Pri MtrCtrl Mode] = 4)
2. Velocity Regulator mode (10:30 [PsnVelTrq Mode A] = 1)
3. Either Case a or Case b is true:
a. The primary feedback 10:1000 [Pri Vel Fb Sel] is set to the Open Loop Virtual Encoder.
b. The alternate feedback 10:1006 [Alt VelFb Sel] is set to the Open Loop Virtual Encoder, 10:1019 [Fb Loss Action] = Auto Tach SW (2),
and a switchover condition happened due to encoder feedback loss fault.
Encoderless Mode is not available in Position mode.
Initial Configuration
If you have configured the drive with the out-of-box recommended default settings or with autotune that is outlined in the previous
chapters, but you still require more performance, skip this section and proceed to Tune the Current Loop (Optional) on page 77.
If the mechanical load is unstable or your control loop gain values are undesirable, then start with this section. However, we advise that you
first follow the tuning flowchart to yield a good stable starting point. See Is Further Tuning Required?
on page 75 for more information.
Follow these steps to bring the drive back to an initial state with default settings.
1. Configure drive parameters by following the Recommended Default Settings
on page 58.
2. Run the drive and adjust 10:906 [System BW] with 10:905 [System C/U Select] = Calculate (0) to achieve the performance you want.
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