YASKAWA SGD7S series Product Manual page 81

5.4 Estimating the Moment of Inertia
5.4.4 Operating Procedure
 Speed Loop Setting Area
Make the speed loop settings in this area.
If the speed loop response is too bad, it will not be possible to measure the moment of
inertia ratio accurately.
The values for the speed loop response that are required for moment of inertia estimation
are set for the default settings. It is normally not necessary to change these settings.
If the default speed loop gain is too high for the machine (i.e., if vibration occurs), lower
the setting. It is not necessary to increase the setting any farther.
 Identification Start Level Group
This is the setting of the moment of inertia calculation starting level.
If the load is large or the machine has low rigidity, the torque limit may be applied, caus-
ing moment of inertia estimation to fail.
If that occurs, estimation may be possible if you double the setting of the start level.
 Edit Buttons
Click the button to display a dialog box to change the settings related to the speed loop
or estimation start level.
 Help Button
Click this button to display guidelines for setting the reference conditions. Make the fol-
lowing settings as required.
• Operate the motor to measure the load moment of inertia of the machine in comparison
• Set the operation mode, reference pattern (maximum acceleration rate, maximum
• Correct measurement of the moment of inertia ratio may not be possible depending on
 Reference Selection Area
Either select the reference pattern for estimation processing from the box, or set the val-
ues in the Detailed Setting Group. Generally speaking, the larger the maximum acceler-
ation rate is, the more accurate the moment of inertia estimation will be.
Set the maximum acceleration range within the possible range of movement considering
the gear ratio, e.g., the pulley diameters or ball screw pitch.
 Confirm Button
Click this button to display the Reference Confirmation Dialog Box.
 Detailed Setting Area
You can change the settings by moving the bars or directly inputting the settings to cre-
ate the required reference pattern.
 Next Button
Click this button to display the Reference Transmission Dialog Box.
 Cancel Button
Click this button to return to the Tuning Dialog Box.
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with the rotor moment of inertia.
speed, and maximum travel distance), and speed loop-related parameters.
the settings. Set suitable settings using the measurement results as reference.
 The travel distance is the distance for one operation in the forward or reverse direction.
During multiple operations, the operation starting position may move in one direction or the
other. Confirm the possible operating range for each measurement or operation.
 Depending on the parameter settings and the moment of inertia of the machine, overshoot-
ing and undershooting may occur and may cause the maximum speed setting to be
exceeded temporarily. Allow sufficient leeway in the settings.
CAUTION