Rockwell Automation 8510 AC Spindle Drive System Programming Manual - Manual (Page 40)

Drive Tuning
Chapter 3
3-37
Gains
The variables for gain are expressed in Per Unit. Per Unit P, I, and Droop
gains are defined as:
P is defined as T/V (units of torque produced for each unit of velocity error)
I is defined as T/V/s (units of torque change per second for each unit velocity error)
Droop is defined as V/T (units of velocity droop for each unit of torque being produced)
Example 3:
The same 1500 rpm, 200 N-m (147.5 lb.-ft.) motor will be used.
If the velocity error is 0.02 Per Unit and P = 20, what is the Per Unit
torque?
T = P x V = 20 x 0.02 = 0.4 Per Unit Torque
What is the torque expressed in N-m (lb.-ft.)?
Torque
200 N-m (147.5 lb.-
ft.)
= 80 N-m (59.0 lb.-ft.) 0.4 =
Spindle Orient Mode Tuning In the Spindle Orient Mode, the 8510 uses the Servo Mode, High Speed
Range parameter settings to control the dynamics of the velocity loop. The
position loop dynamics is controlled by the settings of the ORIENT TUNE
– Orient Speed and ORIENT TUNE – Orient Start parameters.
The actual target position is either preset by the ORIENT TUNE – Preset
Angle parameter or input through the 16 bit digital speed/position inputs.
The actual source of the orient position data is determined by the setting of
the ORIENT TUNE – Position Data parameter.
The ORIENT TUNE – Orient Speed parameter defines the spindle speed
just prior to the start of the final deceleration toward the target position.
The ORIENT TUNE – Orient Start parameter defines the number of
degrees ahead of the target spindle position where the drive begins the final
deceleration to the target position.
When the Orient Command is energized, the spindle is immediately
decelerated to the Orient Speed. When the Orient Start position is reached,
the final deceleration begins. The deceleration to Orient Speed is a simple
velocity ramp without position control. Thus, the spindle may turn as much
as one revolution at Orient Speed before the Orient Start position is
reached.