YASKAWA SGD7S Product Manual page 341

8.13 Manual Tuning
8.13.1 Tuning the Servo Gains
• 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 Operator, Panel Operator, and 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
Model Following Control
You can use model following control to improve response characteristic and shorten position-
ing time. You can use model following control only with position control.
Normally, the parameters that are used for model following control are automatically set along
with the servo gains by executing autotuning or custom tuning. However, you must adjust them
manually in the following cases.
• When the tuning results for autotuning or custom tuning are not acceptable
• When you want to increase the response characteristic higher than that achieved by the tun-
ing results for autotuning or custom tuning
• When you want to determine the servo gains and model following control parameters yourself
8-86
×
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].