Yaskawa SGDS Sigma III Servo Amplifier - Manual (Page 252)

8.6 Servo Gain Adjustment Functions
8-25
Using the Torque Reference Level to Switch Modes (Factory Setting)
With this setting, the speed loop is switched to P control
when the value of torque reference input exceeds the torque
set in parameter Pn10C. The factory default setting for the
torque reference detection point is 200
% of the rated torque
(Pn10C = 200).
Operating Example
If the mode switch function is not being used and the SERVOPACK is always operated with PI control, the speed of the
motor may overshoot or undershoot due to torque saturation during acceleration or deceleration. The mode switch function
suppresses torque saturation and eliminates the overshooting or undershooting of the motor speed.
Using the Speed Reference Level to Switch Modes
With this setting, the speed loop is switched to P control when the value
of speed reference input exceeds the speed set in parameter Pn10D.
Operating Example
In this example, the mode switch is used to reduce the settling time. It is necessary to increase the speed loop gain to reduce
the settling time. Using the mode switch suppresses overshooting and undershooting when speed loop gain is increased.
Motor speed
Reference speed
Speed
Torque Reference
+Pn10C
Torque Reference 0
- Pn10C
PI Control PI Control PI P P
Motor
speed
Time
Overshoot
Undershoot
Motor
speed
Time
Without mode Switching Without mode Switching
Speed reference
Speed
Pn10D
Motor
speed
Time
P Control PI PI Control
Increase speed loop gain
Overshoot
Undershoot
Motor
speed
Time
Setting time
Motor
speed
Motor speed
Speed reference
Long Setting Time
Motor
speed
Without mode Switching Without mode Switching