YASKAWA SGD7S series Product Manual page 57

Before Adjustment: Pn198 = 10000 (100.00%)
Position
reference
speed
Torque
reference
Position
deviation
reference
0 175 350
Time (ms)
Adjustment Example for Less-Deviation Control 2 Viscous
Friction Compensation Coefficients (Pn19B and Pn19D)
For mechanisms that are greatly affected by viscous friction, the effectiveness of torque feed-
forward (Pn198 and Pn199) is reduced. To allow for this, set one of the following parameters.
• Less-Deviation Control 2 Rotary Servomotor Viscous Friction Compensation Coefficient
(Pn19B)
• Less-Deviation Control 2 Linear Servomotor Viscous Friction Compensation Coefficient
(Pn19D)
By setting one of the above parameters, an equivalent viscous friction torque is added to the
torque feedforward.
Set Pn19B to the percentage of the rated torque [N·m] that occurs at a motor speed of 100
-1
min
.
The calculations for the setting of Pn19B are given below.
1.
Operate the motor at a constant speed.
In this procedure, 1,000 min
2.
Use a tracing operation on the SigmaWin+ or other means to measure the torque at the
speed in step 1.
Here, we will assume it was 7.5%.
3.
Calculate the torque at 100 min
• Formula: Torque at speed in step 1 (%) × 100 min
The calculation is as follows for this example:
-1
• 7.5% × 100 min
÷ 1000 min
Therefore, Pn19B is set to 0.75.
525 700 875
-1
is used.
-1
.
-1
÷ Speed in step 1 (min
-1
= 0.75%
3.3 Adjusting Less-Deviation Control 2
3.3.2 Adjustment Example
After Adjustment: Pn198 = 20000 (200.00%)
Position
reference
speed
Torque
reference
Position deviation
is reduced.
Position
deviation
reference
0 175 350 525
Time (ms)
-1
)
700 875
3
3-7