Mitsubishi Electric FR-A720-0.4K Instruction Manual page 229

Position loop gain (Pr. 362 )
When servo torque function is selected using Pr. 358 Servo torque selection , output frequency for generating servo
torque increases to the creep speed of Pr. 352 Creep speed gradually according to the slope set in Pr. 362 Orientation
position loop gain .
Although the operation becomes faster when the value is increased, a machine may hunt, etc.
(7) Orientation operation explanation (during vector control)
Setting the rotation direction (Pr. 393 Orientation selection )
Rotation
Pr. 393 Setting
Direction
0
Pre-orientation
(initial value)
Forward rotation
1
orientation
Reverse rotation
2
orientation
1) Orientation from the current rotation direction
• When the orientation command (X22) is input, the motor speed will
decelerate from the runnig speed to Pr. 351 Orientation speed.
At the same time, the orientation stop position command will be read in.
(The stop position command is determined by the setting of Pr. 350 and Pr.
360. Refer to the right chart.)
• When the orientation switchover speed is reached, the encoder Z phase
pulse will be confirmed, and the mode will change from speed control to
position control (Pr. 362 Orientation position loop gain ).
• The distance to the orientation stop position is calculated at switching of
the control, and the motor decelerates and stops with a set deceleration
pattern (Pr. 399) and the orientation (servo lock) state will be entered.
• When entered in the Pr. 357 Orientation in-position zone, the orientation
completion signal (ORA) will be output.
• The zero point position (origin) can be moved using Pr. 361 Position shift .
If the orientation command (X22) is turned off while the start signal is input, the motor will accelerate toward the
speed of the current speed command. Thus, to stop, turn the forward rotation (reverse rotation) signal off.
2) Orientation from the forward rotation direction
• This method is used to improve the stopping precision and maintain the
mechanical precision when the backlash is large.
• If the motor is running in the forward rotation direction, it will make an
orientation stop with the same method as "orientation from the current
rotation direction".
• If the motor is running in reverse, it will decelerate, the rotation direction
will be changed to forward run, and then orientation stop will be executed.
Orientation is executed from the current rotation direction.
Orientation is executed from the forward rotation direction.
(If the motor is running in reverse, orientation is executed from the
forward rotation direction after deceleration.)
Orientation is executed from the reverse rotation direction.
(If the motor is running in forward, orientation is executed from the
reverse rotation direction after deceleration.)
WARNING
Motor brake and stop operation
Remarks
Speed
(forward rotation)
X22
ORA
Speed
(reverse rotation)
X22
ORA
Speed
(forward rotation)
X22
ORA
Speed
(reverse rotation)
X22
ORA
[t]
OFF
ON
OFF ON
[t]
OFF
ON
OFF ON
[t]
[t]
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