Poor Speed Accuracy (Unstable Speed Of Servo Motor); The Machine Vibrates Unsteadily When It Stops; Overshoot/Undershoot Occurs - Mitsubishi Electric MR-J5-G Series User Manual

Poor speed accuracy (Unstable speed of servo motor)

Possible cause
1.
The servo gain is too low or the response of
the auto tuning is too low.
2.
The servo gain is too high or the response of
the auto tuning is too high.
3.
The torque is insufficient for the large load.
4.
An unintended torque limit has been enabled.
5.
The setting value for the torque limit is
incorrect.
6.
For a servo motor with an electromagnetic
brake, the brake has not been released.
7.
The command from the controller is unstable.
8.
The power supply voltage is lower than
specifications.

The machine vibrates unsteadily when it stops

Possible cause
1.
The servo gain is too low or the response of
the auto tuning is too low.

Overshoot/undershoot occurs

Possible cause
1.
The servo gain is too low or too high. The
response of auto tuning is too low or too high.
2.
The setting of [Pr. PB06 Load to motor inertia
ratio/load to motor mass ratio] is incorrect.
3.
The maximum torque is insufficient due to the
excessive load or the capacity of the servo
motor is insufficient.
4.
The setting of the torque limit value is too
small.
5.
The backlash of the machine part is too large.
Check/action method
Increase the servo gain or the value of [Pr. PA09 Auto tuning response].
Decrease the servo gain to check if the trouble is solved. Alternatively,
decrease the value of [Pr. PA09].
Check the instantaneous torque on the status display ([A]) or with MR
Configurator2. If the torque reaches the maximum torque or the torque limit
value, reduce the load or replace the servo motor with a larger-capacity servo
motor.
On the status display or MR Configurator2, check if TLC (Limiting torque) is
turned on. Cancel the torque limit.
Refer to "Torque limit" in the following manual.
MR-J5 User's Manual (Function)
Increase the torque limit value.
Refer to "Torque limit" in the following manual.
MR-J5 User's Manual (Function)
Turn on the electromagnetic brake power.
Review the command from the controller.
Alternatively, check if the Ethernet cable is disconnected or has other
problems.
Adjust the power supply voltage within the range of specifications.
Check/action method
Increase the servo gain or the value of [Pr. PA09 Auto tuning response].
Check/action method
Adjust the response of auto tuning and readjust the gain.
Check if the setting value of [Pr. PB06] matches the actual load moment of
inertia or load mass. If the value does not match, set the parameter correctly.
Check the instantaneous torque on the status display. Check if the torque
reaches the torque limit value. Keep the torque outside the torque limit value
by increasing the acceleration/deceleration time or by reducing the load.
Alternatively, use a servo motor with a larger capacity.
Check the instantaneous torque on the status display. Check if the torque
reaches the torque limit value.
Increase the torque limit value so that the torque does not reach the limit
value.
Perform an inspection and maintenance of the coupling and the machine.
1 SERVO AMPLIFIER TROUBLESHOOTING
1.4 Trouble which does not trigger an alarm/warning
1
Model
[A]
[G]
[WG]
Model
[A]
[G]
[WG]
Model
[A]
[G]
[WG]
205