7. GENERAL GAIN ADJUSTMENT

7.2.2 Auto tuning mode operation

The block diagram of real-time auto tuning is shown below.

Load inertia

 

 

 

 

 

Automatic setting

 

 

 

 

 

 

moment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Encoder

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Command

Control gains

 

 

 

 

Current

 

 

 

 

 

 

 

 

 

 

 

PG1,VG1

 

 

 

 

 

Motor

 

 

 

 

 

 

 

 

 

 

 

control

 

 

 

 

 

 

 

 

PG2,VG2,VIC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current feedback

 

 

 

 

 

 

 

 

 

 

 

Set 0 or 1 to turn on.

Real-time auto

 

Position/speed

 

 

 

 

 

tuning section

 

 

 

 

 

 

 

 

 

 

 

feedback

 

 

 

 

 

 

 

 

 

 

 

 

Gain table

Parameter No. 2

0 1 0 7

First digit

Third digit Response level setting Auto tuning selection

Load inertia

moment ratio

SW1 estimation section Speed feedback

Parameter No. 34 Load inertia moment ratio estimation value

When a 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 motor. The results of estimation are written to parameter No. 34 (load inertia moment ratio). These results can be confirmed on the status display screen of the servo amplifier display section.

If the value of the load inertia moment ratio is already known or if estimation cannot be made properly,

set " 2 " in parameter No. 2 (auto tuning) to stop the estimation of the load inertia moment ratio (SW1 in above diagram turned off), and set the load inertia moment ratio in parameter No. 34 manually. From the value of parameter No. 34 and the first digit (response level setting) of parameter No. 2, the optimum control 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 6 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.

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Image 149
Mitsubishi Electronics MR-J2S- A Auto tuning mode operation, Block diagram of real-time auto tuning is shown below