 How to Set Parameters for AC Servo Motor?

Initialization Parameters for AC Servo Motor

Before wiring, initialize the parameters.

• On the control card: select the control mode; set the PID parameters to zero; ensure that the default enable signal is off when the control card is powered on; save this state to ensure that the control card is in this state when powered on again.

• On the AC servo motor: set the control mode; set the enable signal to be controlled externally; set the gear ratio of the encoder signal output; set the proportional relationship between the control signal and the motor speed. Generally, it is recommended that the design speed corresponding to the servo operation corresponds to a control voltage of 9V.

Wiring of AC Servo Motor

Turn off the control card and connect the signal line between the control card and the servo. The following lines must be connected: analog output line of the control card, enable signal line, and encoder signal line output by the servo. After checking that the wiring is correct, turn on the servo motor and the control card (and PC) power supply. At this time, the motor should not move and can be easily turned by external force. If not, check the enable signal setting and wiring. Rotate the motor with external force to check whether the control card can correctly detect the change of the motor position. If not, check the encoder signal wiring and settings.

Testing Directions of AC Servo Motor

For a closed-loop control system, if the direction of the feedback signal is incorrect, the consequences are disastrous. Turn on the servo's enable signal through the control card. The servo should rotate at a low speed, which is the legendary "zero drift".

Generally, there will be instructions or parameters to suppress zero drift on the control card. Use this instruction or parameter to see if the motor speed and direction can be controlled by this instruction (parameter).

If it cannot be controlled, check the analog wiring and the parameter settings of the control mode. Confirm that the positive number is given, the motor rotates forward, and the encoder count increases; give a negative number, the motor rotates backward, and the encoder count decreases.

If the motor is loaded and the stroke is limited, do not use this method. Do not test with too high voltage, it is recommended to use below 1V. If the direction is inconsistent, the parameters on the control card or motor can be modified to make them consistent.

Suppressing Zero Drift of AC Servo Motor

In the closed-loop control process, the presence of zero drift will have a certain impact on the control effect, and it should be suppressed. Use the parameter that suppresses zero drift on the control card or servo, carefully adjust it, and make the motor speed approach zero. Since zero drift itself has a certain randomness, the motor speed does not have to be absolutely zero.

Establishing Closed-Loop Control of AC Servo Motor

Once again, release the servo enable signal through the control card, input a small proportional gain on the control card, and as for how small it is, it can only be based on feeling. If you are not sure, enter the smallest value allowed by the control card. Turn on the enable signal for the control card and servo. At this time, the motor should be able to roughly follow the motion instructions.

Adjusting Closed-Loop Parameters of AC Servo Motor

Fine-tune the control parameters to ensure that the motor moves according to the control card instructions. This is a necessary job, and more of it is experience. Here it can only be briefly mentioned.