Baldor BXII installation manual Tuning an axis for current control, Selecting servo loop gains

5.6 Tuning an axis for current control

5.6.1 Selecting servo loop gains

All servo loop parameters default to zero, meaning that the demand output will be zero at power up. Most servo amplifiers can be set to current (torque) control mode or velocity control mode; check that the servo amplifier will operate in the correct mode. The procedure for setting system gains differs slightly for each. To tune an axis for velocity control, go straight to section 5.8. It is recommended that the system is initially tested and tuned with the motor shaft disconnected from other machinery.

Note: The method explained in this section should allow you to gain good control of the motor, but will not necessarily provide the optimum response without further fine-tuning. Unavoidably, this requires a good understanding of the effect of the gain terms.

1.In the Toolbox, click the Fine-tuning icon.

The Fine-tuning window is displayed at the right of the screen. The main area of the WorkBench v5 window displays the Capture window. When tuning tests are performed, this will display a graph representing the response.

2.In the Fine-tuning window, click in the KDERIV box and enter a starting value of 1.

Click Apply and then turn the motor shaft by hand. Repeat this process, slowly increasing the value of KDERIV until you begin to feel some resistance in the motor shaft. The exact value of KDERIV is not critical at this stage.

3.Click in the KPROP box and enter a value that is approximately one quarter of the value of KDERIV. If the motor begins to vibrate, decrease the value of KPROP or increase the value of KDERIV until the vibration stops. Small changes may be all that is necessary.

5-14 Operation MN1904