Adjusting Servo Performance; Setting User Constants; Setting Optimum Position And Speed Loop Gain - YASKAWA SGM Series User Manual

11.3 Adjusting Servo Performance

11.3.1 Setting User Constants

J Position Loop Gain (Cn-001A)
Position loop gain is ideally determined by the specifications of the equipment, but initially
set a level lower than the desired value. (The factory setting is 40 (l/s).)
J Load Moment of Inertia (Cn-0003)
Set the load moment of inertia for the moment of inertia ratio on the motor shaft. (This constant
is factory-set to 100 (%), which is equivalent to the motor moment of inertia.)
J Speed Loop Gain (Cn-0004)
The setting (Hz) of Cn-0004 expresses the speed loop gain characteristics, and is the cutoff
frequency "fc" for the response characteristics of a system with balanced inertia. The value
fc may vary even with the same speed loop gain setting due to fluctuations in load moment of
inertia.
* The factory setting is 40 Hz.
Note Set load moment of inertia (Cn-0003) to 0 (%) so that the speed loop gain (Cn-0004) will be
40 (Hz) or less if the Servomotor is running under no-load conditions.
J Speed Loop Integration Time constant (Cn-0005)
Set Cn-0005 to 20 (ms). (Factory setting)

11.3.2 Setting Optimum Position and Speed Loop Gain

J Speed Overshooting and Vibration
D Incrementally decrease the position loop gain (Cn-001A).
D Incrementally increase the speed loop gain. If the situation worsens when the speed loop
gain is increased, incrementally decrease the gain.
D A certain amount of position loop gain is necessary, so set the acceleration/deceleration
time (Cn-001F to 0021) high if the application cannot handle overshoot.
Gain
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11.3 Adjusting Servo Performance
Frequency f [Hz]
fc: cutoff frequency [Hz]*
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