Mitsubishi Electric FR-A700 Instruction Manual page 74

(4) 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
200rad/s
120rad/s
60% 100%
(initial value)
· 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. 820 Speed control P gain 1 = "60%" (initial value) is equivalent to
120rad/s (speed responce of the motor alone). Increasing the
setting value improves the response level, but a too large gain will
produce vibration and/or unusual noise.
· Decreasing the Pr. 821 Speed control integral time 1 shortens the
return time taken at a speed change. However, a too short time will
Pr.820
generate an overshoot.
Setting
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.
JM
JM: Inertia of the motor
JL: Motor shaft-equivalent load inertia
JM+JL
Adjustment Method
Before operation
Easy gain tuning
69
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