YASKAWA E-7-Series SGD7S Product Manual page 368

For machines for which a high position loop gain (Pn102) cannot be set, overflow alarms can
Information
occur during high-speed operation. If that is the case, you can increase the setting of the fol-
lowing parameter to increase the level for alarm detection.
Use the following condition as a guideline for determining the setting.
Maximum feed speed [reference units/s]

Pn520
If you use a position reference filter, transient deviation will increase due to the filter time con-
stant. When you make the setting, consider deviation accumulation that may result from the
filter.
Position Deviation Overflow Alarm Level
Setting Range
Pn520
1,073,741,823
 Speed Loop Gain
This parameter determines the response characteristic of the speed loop. If the response char-
acteristic of the speed loop is low, it becomes a delay factor for the position loop located out-
side of the speed loop. This will result in overshooting and vibration in the speed reference.
Therefore, setting the speed loop gain as high as possible within the range that will not cause
the machine system to vibrate will produce a stable servo system with a good response char-
acteristic.
Speed Loop Gain
Pn100 Setting Range
10 to 20,000
Load moment of inertia at motor shaft (J
Setting of Pn103 =
Servomotor moment of inertia (L
The default setting of Pn103 (Moment of Inertia Ratio) is 100. Before you tune the servo, calcu-
late the moment of inertia ratio with the above formula and set Pn103 to the calculation result.
Moment of Inertia Ratio
Pn103 Setting Range
0 to 20,000
 Speed Loop Integral Time Constant
To enable response to even small inputs, the speed loop has an integral element. The integral
element becomes a delay factor in the servo system. If the time constant is set too high, over-
shooting will occur, positioning settling time will increase, and the response characteristic will
suffer.
Speed Loop Integral Time Constant
Pn101 Setting Range
15 to 51,200
 Torque Reference Filter
As shown in the following diagram, the torque reference filter contains a first order lag filter and
notch filters arranged in series, and each filter operates independently.
The notch filters can be enabled and disabled with Pn408 = n.XX and Pn416 = n.XXX.

2.0
Pn102 ÷ 10 (1/s)
Setting Unit
1 to 1 reference
unit
Setting Unit Default Setting
0.1 Hz
)
M
Setting Unit Default Setting
1%
Setting Unit Default Setting
0.01 ms
8.12.1 Tuning the Servo Gains
Default Setting When Enabled Classification
5,242,880 Immediately
Speed
When Enabled
400 Immediately
)
L ×100(%)
Speed
When Enabled
100 Immediately
Speed
When Enabled
2,000 Immediately
8.12 Manual Tuning
Position
Setup
Position Torque
Classifica-
tion
Tuning
Position Torque
Classifica-
tion
Tuning
Position
Classifica-
tion
Tuning
8-69
8