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SV200 DC Hardware Manual
920-0126A
4/14/2017
11.3.2 Position loop gain (KF)
This parameter is the primary gain term for minimizing the position error. Increasing KF will increase stiffness and reduce settling time.
However, it might cause vibration if increased too much. This is simplest part of the PID loop; the drive will apply current to the motor
in direct proportion to the error. Because the current controls the torque output from the motor, increasing this gain will increase the
magnitude of torque in direct proportion to the position error. Here’s an example: if the motor were standing still, and you suddenly
turned the shaft by hand, you’d want the drive to increase the motor current so that it goes back into position. The further you disturb
the motor from its target position, the more the torque will increase.
As shown below, if KF is small, position error will be high at all times (during acceleration, constant velocity, and deceleration)
As shown below, if the KF value is set appropriately, the position error during acceleration and deceleration will settle very quickly, and
position error of ±1 count can be achieved during constant velocity as well as when the motor comes to rest at its target position.
