YASKAWA SGD7S-****20A Series Product Manual page 366

8.13 Manual Tuning
8.13.1 Tuning the Servo Gains
 When Pn10B = n.0 (PI Control)
Guidelines are given below for gain settings 1.
The same guidelines apply to gain settings 2 (Pn104, Pn105, Pn106, and Pn412).
• Speed Loop Gain (Pn100 [Hz]) and Position Loop Gain (Pn102 [/s])
Stable gain: Pn102 [/s] ≤ 2π × Pn100/4 [Hz]
Critical gain: Pn102 [/s] < 2π × Pn100 [Hz]
• Speed Loop Gain (Pn100 [Hz]) and Speed Loop Integral Time Constant (Pn101 [ms])
Stable gain: Pn101 [ms] ≥ 4,000/(2π × Pn100 [Hz])
Critical gain: Pn101 [ms] > 1,000/(2π × Pn100 [Hz])
• Speed Loop Gain (Pn100 [Hz]) and First Stage First Torque Reference Filter Time Constant
(Pn401 [ms])
Stable gain: Pn401 [ms] ≤ 1,000/(2π × Pn100 [Hz] × 4)
Critical gain: Pn401 [ms] < 1,000/(2π × Pn100 [Hz] × 1)
• Speed Loop Gain (Pn100 [Hz]) and Second Stage Second Torque Reference Filter Frequency
(Pn40F [Hz])
Critical gain: Pn40F [Hz] > 4 × Pn100 [Hz]
Note: Set the Second Stage Second Torque Reference Filter Q Value (Pn410) to 0.70.
• Speed Loop Gain (Pn100 [Hz]) and First Stage Notch Filter Frequency (Pn409 [Hz]) (or Sec-
ond Stage Notch Filter Frequency (Pn40C [Hz]))
Critical gain: Pn409 [Hz] > 4
• Speed Loop Gain (Pn100 [Hz]) and Speed Feedback Filter Time Constant (Pn308 [ms])
Stable gain: Pn308 [ms] ≤ 1,000/(2π × Pn100 [Hz] × 4)
Critical gain: Pn308 [ms] < 1,000/(2π × Pn100 [Hz] × 1)
 When Pn10B = n.1 (I-P Control)
Guidelines are given below for gain settings 1.
The same guidelines apply to gain settings 2 (Pn104, Pn105, Pn106, and Pn412).
For I-P control, the relationships between the speed loop integral time constant, speed loop
gain, and position loop gain are different from the relationships for PI control. The relationship
between other servo gains is the same as for PI control.
• Speed Loop Gain (Pn100 [Hz]) and Speed Loop Integral Time Constant (Pn101 [ms])
Stable gain: Pn100 [Hz] ≥ 320/Pn101 [ms]
• Position Loop Gain (Pn102 [/s]) and Speed Loop Integral Time Constant (Pn101 [ms])
Stable gain: Pn102 [/s] ≤ 320/Pn101 [ms]
Information
 Decimal Points in Parameter Settings
For the SGD7S SERVOPACKs, decimal places are given for the settings of parameters on the
Digital Operatorand in the manual. For example with Pn100 (Speed Loop Gain), Pn100 = 40.0
is used to indicate a setting of 40.0 Hz. In the following adjusted value guidelines, the decimal
places are also given.
Example
8-88
×
Pn100 [Hz]
Selecting the Speed Loop Control Method (PI Control or I-P Control)
Usually, I-P control is effective for high-speed positioning and high-speed, high-precision pro-
cessing applications. With I-P control, you can use a lower position loop gain than for PI con-
trol to reduce the positioning time and reduce arc radius reduction. However, if you can use
mode switching to change to proportional control to achieve the desired application, then
using PI control would be the normal choice.
• Speed Loop Gain (Pn100 [Hz]) and Speed Loop Integral Time Constant (Pn101 [ms])
Stable gain: Pn101 [ms] ≥ 4,000/(2π × Pn100 [Hz]), therefore
If Pn100 = 40.0 [Hz], then Pn101 = 4,000/(2π × 40.0) ≈ 15.92 [ms].