Mitsubishi Electric MR-J4, Instruction Manual

Page: 280 / 794

6. NORMAL GAIN ADJUSTMENT
6 - 15
6.3.2 Auto tuning mode basis
The block diagram of real-time auto tuning is shown below.
Loop gain
PG1, PG2,
VG2, VIC
Current
control
Load to motor
inertia ratio
estimation section
Gain table
[Pr. PB06 Load to
motor inertia ratio]
Response
level setting
Gain adjustment mode selection
[Pr. PA08]
+
-
+
-
Real-time
auto tuning section
Set 0 or 1 to turn on.
Switch
Current feedback
Position/speed
feedback
Speed feedback
Load moment
of inertia
Encoder
Command
Automatic setting
[Pr. PA09]
M
Servo motor
0 0 0
When a servo motor is accelerated/decelerated, the load to motor inertia ratio estimation section always
estimates the load to motor inertia ratio from the current and speed of the servo motor. The results of
estimation are written to [Pr. PB06 Load to motor inertia ratio]. These results can be confirmed on the status
display screen of the MR Configurator2.
If you have already known the value of the load to motor inertia ratio or failed to estimate, set "Gain
adjustment mode selection" to "Auto tuning mode 2 (_ _ _ 2)" in [Pr. PA08] to stop the estimation (turning off
the switch in above diagram), and set the load to motor inertia ratio ([Pr. PB06]) manually.
From the preset load to motor inertia ratio ([Pr. PB06]) value and response ([Pr. PA09]), the optimum loop
gains are automatically set on the basis of the internal gain table.
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 loop gain saved in the EEP-ROM being used
as an initial value.
POINT
If sudden disturbance torque is imposed during operation, the load to motor
inertia ratio may be misestimated temporarily. In such a case, set "Gain
adjustment mode selection" to "Auto tuning mode 2 (_ _ _ 2)" in [Pr. PA08] and
then set the correct load to motor inertia ratio in [Pr. PB06].
When any of the auto tuning mode 1 and auto tuning mode settings is changed
to the manual mode 2 setting, the current loop gains and load to motor inertia
ratio estimation value are saved in the EEP-ROM.