Instruction Manual

7 - 4
7. GENERAL GAIN ADJUSTMENT
7.2.2 Auto tuning mode operation
The block diagram of real-time auto tuning is shown below.
Servo
motor
Command
Automatic setting
Control gains
PG1,VG1
PG2,VG2,VIC
Current
control
Current feedback
Load inertia
moment
Encoder
Position/speed
feedback
Real-time auto
tuning section
Speed feedback
Load inertia
moment ratio
estimation section
Gain
table
Parameter No. 2
Gain adjustment
mode selection
First digit
Response level
setting
Parameter No. 34
Load inertia moment
ratio estimation value
Set 0 or 1 to turn on.
Switch
When a servo motor is accelerated/decelerated, the load inertia moment ratio estimation section always
estimates the load inertia moment ratio from the current and speed of the servo motor. The results of
estimation are written to parameter No. 34 (the ratio of load inertia moment to servo motor). These
results can be confirmed on the status display screen of the MR Configurator (servo configuration
software) section.
If the value of the load inertia moment ratio is already known or if estimation cannot be made properly,
chose the "auto tuning mode 2" (parameter No.2:
2 ) to stop the estimation of the load inertia
moment ratio (Switch in above diagram turned off), and set the load inertia moment ratio (parameter No.
34) manually.
From the preset load inertia moment ratio (parameter No. 34) value and response level (The first digit of
parameter No. 2), the optimum control gains are automatically set on the basis of the internal gain tale.
The auto tuning results are saved in the EEP-ROM of the servo amplifier every 60 minutes since power-
on. At power-on, auto tuning is performed with the value of each control gain saved in the EEP-ROM
being used as an initial value.
POINT
If sudden disturbance torque is imposed during operation, the estimation
of the inertia moment ratio may malfunction temporarily. In such a case,
choose the "auto tuning mode 2" (parameter No. 2: 020
) and set the
correct load inertia moment ratio in parameter No. 34.
When any of the auto tuning mode 1, auto tuning mode 2 and manual
mode 1 settings is changed to the manual mode 2 setting, the current
control gains and load inertia moment ratio estimation value are saved in
the EEP-ROM.