Speed Control Gain Adjustment - Mitsubishi Electric A800 Plus Series Function Manual

• If using a motor falling under the following conditions, set the value of Pr.9 Electronic thermal O/L relay as shown below
after tuning is complete.
a) If the rated power supply of the motor is 200/220 V (400/440 V) 60 Hz, set the rated motor current multiplied by 1.1 in
Pr.9.
b) If using a motor with a temperature detector such as PTC thermistor and Klixon and performs motor overheat
protection, set Pr.9 = "0" (disables the motor overheat protection feature of the inverter).
NOTE
• An instantaneous power failure occurring during tuning will result in a tuning error. After power is restored, the inverter starts
normal operation. Therefore, when the STF (STR) signal is ON, the motor runs in the forward (reverse) rotation.
• Any alarm occurring during tuning is handled as in the normal operation. Note that even if a retry operation has been set,
retry is not performed.
• The set frequency monitor displayed during the offline auto tuning is 0 Hz.
Caution
 Note that the motor may start running suddenly.
 For the offline auto tuning in vertical lift applications, etc., caution is required to avoid falling due to
insufficient torque.
3.4.3

Speed control gain adjustment

• The load inertia ratio (load moment of inertia) for the motor is calculated from the torque command and rotation speed
during motor driving by the vector control. Because the optimum gain for speed control of dancer feedback / tension sensor
feedback is calculated automatically from the load inertia ratio and the response level, the work required for gain
adjustment is reduced (Easy gain tuning).
• The load inertia ratio can be entered manually if you already know the ratio.
• Manual gain adjustment is useful for achieving optimum machine performance or improving unfavorable conditions, such
as vibration and acoustic noise during operation with high load inertia.
• For gain adjustment, rolls of minimum, medium, and maximum diameters are used.
POINT POINT
• If a roll of medium diameter is not available, refer to the procedure for the case where the medium-diameter roll is not
available ("No medium-diameter roll").
Adjustment by easy gain tuning (recommended)
1
Installation of the minimum-diameter roll
Install the minimum-diameter roll.
2
Easy gain tuning response level setting (tuning with the minimum-diameter roll)
Set the response level in Pr.818 Easy gain tuning response level setting.
Setting this parameter higher improves the trackability for commands, but setting it too high causes vibration. Set
the value measured shortly before vibration occurs in Pr.818.
Pr.818 setting
Response level
Estimated mechanical
resonance frequency (Hz)
Parameter setting procedure for dancer feedback speed control
1 2 3 4 5 6 7
Slow response Medium response
8 10 12 15 18 22 28
DANCER FEEDBACK SPEED CONTROL
8 9 10 11 12 13 14
Fast response
34 42 52 64 79 98 122 150
3
15
53