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Sigma II User's Manual
Operating Example
In this example, the mode switch is used to reduce setting time. Generally, speed
loop gain must be increased to reduce setting time. Using the mode switch sup-
presses the occurrence of overshoot and undershoot as speed loop gain is increased.
Without mode switch
Speed reference
Motor
speed
Long setting time
Acceleration Used as Detection Point
If motor acceleration exceeds the value set in parameter Pn10E, the speed loop
switches to P control.
Operating Example
If the system is always in PI control without using the mode switch function, the
speed of the motor may overshoot or undershoot due to torque saturation at the time
of the acceleration or deceleration of the motor. The mode switch function sup-
presses torque saturation and eliminates motor speed overshoot or undershoot.
Without mode switch
Motor
speed
Motor speed
Increase speed loop gain.
With mode switch
Motor
speed
Setting time
Reference speed
Speed
+Pn10E
Acceleration 0
-Pn10E
PI control
P control
Overshoot
Undershoot
Time
Without mode switch
Motor
speed
Suppress overshooting
and undershooting.
Motor speed
Motor acceleration
PI control
PI control
P control
With mode switch
Motor
speed
6-13
Chapter 6: Servo Adjustment
Overshoot
Undershoot
Time
Time
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