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Gemini GV Hardware Installation Guide
Tuning Procedures
During the Express Setup procedure in Chapter 2 Installation, the drive uses
default values for tuning parameters, based upon the motor information you
entered. That procedure assumes that the motor is unloaded. In the following
tuning procedures, you will enter in system information that will characterize the
load on the motor.
If you are operating the Gemini drive in torque mode, it is not necessary for you to
enter in motor load information. The default tuning parameters for torque mode
are set to provide suitable motor performance. Should you wish to modify the
default values and fine tune you system, proceed to the Torque Mode Tuning
section below.
The default tuning parameters for velocity and position modes are set to provide
good, stiff motor shaft performance for a given load setting. With the default
tuning parameters set in the Express Setup procedure, you need only set the system
load-to-rotor inertia ratio and your system will be tuned.
Entering Load Settings
The main load setting you will adjust is LJRAT, which is the load-to-rotor inertia
value for your system. The more accurately you know this value, the closer your
tuning bandwidth settings will correspond to the actual dynamic performance of
your system. If you only know this value approximately, you can adjust this value
until you achieve the system performance you desire. The total system inertia is
given by the following formula:
Total system inertia = motor rotor inertia*(1 + LJRAT)
If your system has significant mechanical damping, you will also want to adjust
the LDAMP setting which specifies system damping provided by the load. If you
know that you have significant damping in your system from your load but do not
know its exact value, you can adjust this value until you achieve the system
performance that you desire.
Both the LJRAT and the LDAMP values can be set in the Full Configuration
section of Pocket Motion Planner or in the Full Setup section of the Gemini wizard
in Motion Planner. These values can also be set in the terminal modes of Pocket
Motion Planner and Motion Planner. During the tuning process you may want to
use the terminal emulator to establish appropriate values for these parameters and
then upload and save the drive’s full configuration settings for use with other units.
Torque Mode Tuning
For most applications, the default tuning values for your drive/motor combination
from the Express Setup procedure in Chapter 2 Installation will provide good
performance. Use the following procedures if you need to adjust these values.
WARNING
This procedure causes the motor shaft to move. Make sure that shaft motion will
not damage equipment or injure personnel.
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