6.2 High-speed Positioning
6 -9
J
J
Methods for Using Proportional Control
Proportional control can be used in the following two ways.
D
When operation isperformed by sending speed referencesfrom the host controllerto theSer-
vopack, the host controller can selectively use P control mode for particular conditionsonly.
This method can suppress overshooting and shorten setting time. Refer to
6.2.5 Using Mode
Switch
for particular conditions.
D
If PI control mode is used when the speed reference has a reference offset, the motor may
rotate at a very slow speed and fail to stop even if 0 is specified as a speed reference. In this
case, use P control mode to stop the motor.
6.2.4 Setting Speed Bias
The settling time for positioning can be reduced by assigning bias to the speed reference block
in the Servopack. To assign bias, use the following constants.
Pn107
Bias
Unit:
r/min
Setting
Range:
0 to 450
Factory
Setting:
0
Position Control
Pn108
Bias Addition
Width
Unit:
Reference
units
Setting
Range:
0 to 250
Factory
Setting:
7
Position Control
Set the constants to shorten the time required for positioning according to the application.
The bias increment width (Pn108) is expressed by a error pulse width that determine the timing
of giving bias input (Pn107). The bias input is ON if the error pulse width exceeds the value set
in Pn108.
Error pulse
Internal speed reference
Pn107
Bias increment width
Pn108
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