Mitsubishi Electric FR-A700 Instruction Manual page 463

Parameter
● Servo rigidity adjustment (Pr. 362, Pr. 396 to Pr. 398)
To increase the servo rigidity
following procedures.
Increase the Pr. 362 "Orientation position loop gain" value to the extent that rocking
not occur during orientation stop.
Increase Pr. 396 and Pr. 397 at the same rate.
Generally adjust Pr. 396 in the range from 10 to 100, and Pr. 397 from 0.1 to 1.0s. (Note
that these do not need to be set to the same rate.)
EXAMPLE
When the Pr. 396 value is multiplied by 1.2, divide the Pr. 397 value by 1.2. If vibration
occurs during orientation stop, the scale cannot be raised any higher.
Pr. 398 is the lag/advance compensation gain.
The limit cycle
stably. However, the torque in regard to the position deviation will drop, and the motor will
stop with deviation.
NOTE Application of lag/advance control and PI control
PI control can be applied by setting Pr. 398 to 0. Normally, the lag/advance control is selec-
ted. Note that PI control shoud be used when using a machine with a high spindle stationary
friction torque and requires a stopping position precision.
Servo rigidity: This is the response when a position control loop is configured.
When the servo rigidity is raised, the holding force will increase, the running will stabilize,
but vibration will occur easily.
When the servo rigidity is lowered, the holding force will drop, and the setting time will
increase.
Rocking: Movement in which return occurs if the stopping position is exceeded.
Limit cycle: This is a phenomenon that generates ± continuous vibration centering on the
target position.
FR-A700 EC
during orientation stop using Pr. 396 or Pr. 397 , adjust with the
can be prevented by increasing the value, and the running can be stopped
Motor brake and stop operation
does
6 - 283