Mitsubishi Electric 800 Series Instruction Manual page 166

Speed control under Real sensorless vector control, vector control, PM sensorless vector
Block diagram of easy gain tuning function
<Vector control>
Command
NOTE
• Easy gain tuning is valid for the first motor. When applying the second motor (RT signal is ON), tuning is not performed.
Execution procedure for easy gain tuning (Pr.819 = "1" Load inertia ratio
automatic calculation)
Easy gain tuning (load inertia ratio automatic calculation) is only valid in the speed control and position control modes of
vector control. It is invalid under torque control, V/F control, Advanced magnetic flux vector control, Real sensorless vector
control, and PM sensorless vector control.
1) 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. The following
figure shows the relationship between the setting and the response level.
Pr. 818 setting
Response level
Guideline of
mechanical resonance
frequency (Hz)
Inverter
application
2) The load inertia ratio is calculated during acceleration/deceleration, and from this value and the value of Pr.818 Easy
gain tuning response level setting, the gain for each control is set automatically. Pr.880 Load inertia ratio is used as
the initial value of the load inertia ratio when performing tuning. During tuning, the calculated value is set in Pr.880.
The calculation of the load inertia ratio may take excessive time or otherwise not be performed properly if the
following conditions are not satisfied.
•The time in acceleration/deceleration driving until 1500 r/min is reached in 5 s or less.
•The rotation speed in driving is 150 r/min or higher.
•The acceleration/deceleration torque is 10% or higher.
•No sudden external disturbances during acceleration/deceleration.
•The load inertia ratio is about 30-fold or lower.
•No gear backlash or belt sagging.
Automatic setting
Speed control/position loop gain
+
Model speed control gain
-
[Pr.820, Pr.821, Pr.828, Pr.422]
ON when [Pr.819 = "1, 2"]
Gain table Load inertia ratio
[Pr.880]
Response level
setting [Pr.818]
1 2 3 4 5
Slowest
response
8 10 12 15 18
Large
conveyor
Arm robot
+
Current
control
-
Torque command
ON when
[Pr.819 = "1"]
Load inertia
ratio estimation
section
Speed/position feedback
6 7 8 9 10 11 12
Middle
response
22 28 34 42 52 64 79
General machine
tool, conveyor
Precision
machine tool
control
Load
inertia
moment
Detector
Motor Encoder
Actual motor speed
13 14 15
Fastest
response
98 122 150
PARAMETERS
5
165