Compensating The Speed Controller; Offset And Speed Compensation - Quin Q-drive Installation & User Manual

Q-Drive Installation Manual
8.6

Compensating the speed controller

Optimizing the performance of the motor over the whole speed range can be achieved
by adjusting the drive amplifiers Proportional Gain and Integral Gain parameters.
Connect a Personal computer to the amplifier and run the QDRIVE.EXE configuration
program:
a) Set the value of both proportional (KP) and integral (KI) gain to a value of
10, this represents a very low gain setting.
b) Connect an oscilloscope between measuring points on J1, pins 9 and 10, pin
9 is signal and pin 10 is ground.
c) Switch on the servo-amplifier and close the enable contact.
d) Apply a low command speed voltage (<100 m V)
e) Increase the value of the Integral Gain parameter whilst ensuring that the
following factors are maintained:
i good static torque
i smooth shaft rotation
f) Apply a step function of 2 volts to the command input and monitor the
response of the drive using an oscilloscope. One of the three following results
will occur:
i The signal shows several oscillations, this means the system is under
damped, in this case increase the Proportional Gain value
ii The motor is noisy, this means that the motor is over damped, in which
case decrease the Proportional Gain value
iii The signal shows only one small overshoot, this indicates critical
damping has been achieved and therefore the speed loop overshoot is
optimized
g) When the f iii) condition is achieved, save the gains obtained with key <F2>.
8.6.1

Offset and speed compensation

a) Offset compensation
The setting of the servo-amplifier speed offset is done with the offset control
parameter in the QDRIVE.EXE software.
The setting of the offset can be done with or without the position controller.
If a position controller, such a Quin PTS unit, is used then all of the controller
gain parameters must be set to zero. Having set the controller gain parameters
to zero enable the controller output and adjust the servo-amplifier offset
compensation value until the motor stops moving. There will probably be a
range of values where the motor appears to be stationary, find the limits of
this range and set the value to the mid point. To set the offset value without a
controller attached then short out the command input terminals and adjust the
offset value. Again there will probably be a range of values which result in
Page 52 Copyright © 1996 Quin Systems Ltd.
Issue 1.5