Mitsubishi Electric FR-E700EX Instruction Manual page 83

 Actual speed response is calculated as below when load inertia is applied.
Actual speed response = Speed response of the motor alone 
Load
fluctuation
Rotation
speed
 Adjust in the following procedure:
1) Change the Pr.820 setting so that the actual response becomes 100 rad/s to 200 rad/s.
(Example) When setting the actual speed response to 200 rad/s with double the load inertia
Actual speed response = Speed response of themotor alone 
Speed response of themotor alone 
200rad/s =
Speed response of the motor alone = 200rad/s3 = 600rad/s
2) Set a reciprocal of 1/20 to 1/5 of the actual speed response in Pr.821.
(Example 1) With the actual speed response of 200 rad/s, and with setting Pr.821 to 1/20 of the speed response
1
Pr.821
=
200rad/s 
3) Check that the motor rotation speed and torque current command value are stable.
If the motor rotation speed or torque current command is not stable, decrease the actual speed response.
Adjust the gain following the procedure below, as required.
Movement/
No.
condition
Set Pr.820 and Pr.821 higher.
Load inertia is too Pr.820
1
high.
Pr.821
Set Pr.820 lower and Pr.821 higher.
Vibration or
acoustic noise is Pr.820
2
generated from
machines.
Pr.821
Set Pr.820 higher.
3
Response is slow.
Pr.820
Set Pr.821 lower.
Return time
4
(response time) is
Lower Pr.821 by half the current setting and set a value that satisfies the following condition: The
long. setting immediately before overshoots or unstable movements stop occurring 0.8 to 0.9
Set Pr.821 higher.
Overshoots or
5
unstable
Raise Pr.821 by double the current setting and set a value that satisfies the following condition: The
movements occur. setting immediately before overshoots or unstable movements stop occurring 0.8 to 0.9
Setting the proportional gain higher
speeds up the response and reduces the speed fluctuation here.
Setting the integral time lower shortens the return time here.
=0.100s
1
20
If acceleration is slow, raise the setting by 10%s and set a value that satisfies the following
condition: The setting immediately before vibration/ noise starts occurring 0.8 to 0.9
If overshoots occur, raise the setting by double the setting and set a value that satisfies the
following condition: The setting where overshoots stop occurring 0.8 to 0.9
Lower the setting by 10%s and set a value that satisfies the following condition: The setting
immediately before vibration/noise starts occurring 0.8 to 0.9
If overshoots occur, raise the setting by double the setting and set a value that satisfies the
following condition: The setting where overshoots stop occurring 0.8 to 0.9
If acceleration is slow, raise the setting by 5%s and set a value that satisfies the following
condition: The setting immediately before vibration/noise starts occurring 0.8 to 0.9
JM: Motor inertia
JM
JL: Load inertia converted as the motor
JM+JL
axis inertia
JM: Motor inertia
JM
JL: Load inertia converted as
JM+JL
JM
JM+2JM
Set Pr.820 = "300%".
Adjustment method
Speed control
the motor axis inertia
81
4