Yaskawa Large Capacity Sigma II Series - Manual (Page 196)

5.2 High-speed Positioning
5-13
5
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 suppresses torque
saturation and eliminates the overshooting or undershooting of the speed of the motor.
Error Pulse Used as Detection Point
This setting is enabled for position control operation only.
If an error pulse exceeds the value set in parameter Pn10F, the speed loop switches to P con-
trol.
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 suppresses the
occurrence of overshooting and undershooting when speed loop gain is increased.
EXAMPLE
Overshooting
Under-
shooting
Motor
speed
Time
Without mode switch
With mode switch
Motor
speed
Time
Motor speed
Reference
Speed
Pn10F
Deviation
Pulse
Time
P control PI control PI control
EXAMPLE
Motor speed Speed reference
Without mode switch
Long setting time
Increase speed loop gain.
Overshooting
Without mode switch
With mode switch function
Setting time
Motor
speed
Motor
speed
Motor
speed Under-
shooting
Time
Suppress overshooting
and undershooting.