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(5) Manual input speed control gain adjustment
· Make adjustment when any of such phenomena as unusual machine vibration/noise, low response level and
overshoot has occurred.
Proportional gain
200(100)rad/s
120(60)rad/s
60%
(initial value)
* The values for FR-A720-02880 or higher, FR-A740-
01440 or higher or for Real sensorless vector control
are indicated in parenthesis.
· When there is load inertia, the actual speed gain is as given below.
Load
fluctuation
Speed
Actual speed gain = speed gain of motor without load ×
· Adjustment procedures are as below:
1)Check the conditions and simultaneously change the Pr. 820 value.
2)If you cannot make proper adjustment, change the Pr. 821 value and repeat step 1).
Phenomenon/
No.
Condition
Load inertia
1
is large
Vibration/noise
2
generated from
mechanical system
3
Slow response
Long return time
4
(response time)
Overshoot
5
or unstable
phenomenon occurs.
REMARKS
· When making manual input gain adjustment, set "0" (without easy gain tuning) (initial value) in Pr. 819
selection
.
· Pr. 830 Speed control P gain 2 and Pr. 831 Speed control integral time 2 are valid when the RT terminal is switched ON. Make
adjustments in the same way as Pr. 820 and Pr. 821.
· Pr. 820 Speed control P gain 1 = "60%" (initial value) is equivalent to
120rad/s (speed response of the motor alone). (Half the value for
FR-A720-02880 or higher, FR-A740-01440 or higher or for Real
sensorless vector control.) Increasing the setting value improves
the response level, but a too large gain will produce vibration and/or
unusual noise.
Pr.820
Setting
· Decreasing the Pr. 821 Speed control integral time 1 shortens the
100%
return time taken at a speed change. However, a too short time will
generate an overshoot.
Since increasing the proportional gain enhances the
response level and decreases the speed fluctuation.
Decreasing the integral time shortens the return time taken.
Set the Pr. 820 and Pr. 821 values a little higher.
When a speed rise is slow, increase the value 10% by 10% until just before
Pr. 820
vibration/noise is produced, and set about 0.8 to 0.9 of that value.
If an overshoot occurs, double the value until an overshoot does not occur, and
Pr. 821
set about 0.8 to 0.9 of that value.
Set the Pr. 820 value a little lower and the Pr. 821 value a little higher.
Decrease the value 10% by 10% until just before vibration/noise is not produced,
Pr. 820
and set about 0.8 to 0.9 of that value.
If an overshoot occurs, double the value until an overshoot does not occur, and
Pr. 821
set about 0.8 to 0.9 of that value.
Set the Pr. 820 value a little higher.
When a speed rise is slow, increase the value 5% by 5% until just before
Pr. 820
vibration/noise is produced, and set about 0.8 to 0.9 of that value.
Set the Pr. 821 value a little lower.
Decrease the Pr. 821 value by half until just before an overshoot or the unstable phenomenon
does not occur, and set about 0.8 to 0.9 of that value.
Set the Pr. 821 value a little higher.
Increase the Pr. 821 value double by double until just before an overshoot or the unstable
phenomenon does not occur, and set about 0.8 to 0.9 of that value.
Speed control by Real sensorless
vector control, vector control
JM
JM: Inertia of the motor
JL: Motor shaft-equivalent load inertia
JM+JL
Adjustment Method
4
Easy gain tuning
107
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