Mitsubishi Electric FR-A760 Series Instruction Manual page 103

Speed control by real sensorless vector
control, vector control
(2) Easy gain tuning execution procedure (Pr. 819 = "1" load inertia ratio automatic estimation)
Easy gain tuning (load inertia ratio automatic
estimation) is valid only in the speed control or
position control mode under vector control.
It is invalid under torque control, V/F control,
advanced magnetic flux vector control and real
sensorless vector control.
1) Set the response level using Pr. 818 Easy gain
tuning response level setting.
Refer to the diagram on the right and set the
response level.
Increasing the value will improve trackability
to the command, but too high value will
generate vibration. The relationship between
the setting and response level are shown on
the right.
2) Each control gain is automatically set from the
load inertia ratio
acceleration/deceleration operation and the Pr. 818 Easy gain tuning response level setting value.
Pr. 880 Load inertia ratio is used as the initial value of the load inertia ratio for tuning. Estimated value is set in Pr.
880 during tuning.
The load inertia ratio may not be estimated well, e.g. it takes a long time for estimation, if the following
conditions are not satisfied.
· Time taken for acceleration/deceleration to reach 1500r/min is 5s or less.
· Speed is 150r/min or more.
· Acceleration/deceleration torque is 10% or more of the rated torque.
· Abrupt disturbance is not applied during acceleration/deceleration.
· Load inertia ratio is approx. 30 times or less.
· No gear backlash nor belt looseness is found.
3) Press or
external operation is the STF or STR signal.)
(3) Easy gain tuning execution procedure (Pr.819 = "2" load inertia manual input)
Easy gain tuning (load inertia ratio manual input) is valid only in the speed control mode under real sensorless vector
control or in the speed control or position control mode under vector control.
1) Set the load inertia ratio to the motor in Pr. 880 Load inertia ratio.
2) Set "2" (with easy gain tuning) in Pr. 819 Easy gain tuning selection. Then, Pr. 820 Speed control P gain 1 and Pr. 821
Speed control integral time 1 are automaticaly set by gain calculation.
Operation is performed in a gain adjusted status from the next operation.
3) Perform a test run and set the response level in Pr. 818 Easy gain tuning response level setting. Increasing the value will
improve trackability to the command, but too high value will generate vibration. (When "2" (parameter write enabled
during operation) is set in Pr. 77 Parameter write selection , response level adjustment can be made during operation.)
REMARKS
· When "1 or 2" is set in Pr. 819 and then returned the Pr. 819 setting to "0" after tuning is executed, tuning results which are set in
each parameter remain unchanged.
· When good tuning accuracy is not obtained after executing easy gain tuning due to disturbance and such, perform fine
adjustment by manual input. Set "0" (without easy gain tuning) in Pr. 819.
92
estimated during
to estimate the load inertia ratio or calculate gain any time. (The operation command for
Pr. 818 setting 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Slow
Response level
response
Guideline of
8 10 12 15 18 22 28 34 42 52 64 79 98 122 150
mechanical resonance
frequency (Hz)
Large conveyor
Middle
response response
General machine tool,
conveyor
Arm robot
Precision
machine tool
Fast