Rockwell Automation 8510 AC Spindle Drive System Programming Manual - Manual (Page 36)

3 Chapter
3-33
Drive Tuning
Chapter Objectives Chapter 3 provides details of the principles and process of tuning the 8510
drive for optimum operation. This chapter is designed to help the user
understand the tuning process and anticipate the results of changes in
tuning parameters. In addition, the Per Unit system of measure is explained
in detail.
Tuning Introduction The purpose of tuning a drive is to achieve the required stability,
bandwidth, and stiffness. Stability is the ability of the drive to regulate
speed or position without oscillation or excessive overshoot. Bandwidth is
related to the quickness of drive response to changing commands. Stiffness
is the ability of the drive to resist external load disturbances.
Tuning closed loop feedback systems can be complicated. There is
however, an organized approach for the typical machine tool as described
below.
•
P Gain is strongly related to bandwidth
•
I Gain is strongly related to stiffness
•
Both P and I Gains are related to stability, if either is too high, the
system will be unstable
When building identical machines in a production environment, only the
first machine should require tuning. All others should perform identically
by simply presetting the parameter values determined while tuning the first
machine.
Tuning Requirements The 8510 drive provides multiple parameter sets to allow optimum
performance to be achieved with multi-speed gearboxes, dual winding
motors, and widely varying operating conditions. Each parameter set
provides unique tuning parameters for spindle, high speed servo, low speed
servo, and spindle orient modes. Each parameter set and its respective
operating modes used in the application will require individual tuning
according to the following procedure. For best results, it is recommended
that an oscilloscope be used to observe the results of drive tuning, however,
acceptable results can often be achieved by simply observing the spindle
and listening to the drive and motor during the tuning process.