Liu, Z.K. Liang, H. JACoW Publishing Geneva, Switzerland A quick scanning monochromator built for Quick EXAFS experiments needs to perform 2 kinds of movements, one is fast movements in an oscillation way of the spindle, the other is step scan mode. Servo control has never been used on quick scanning monochromators. To verify the feasibility of the 2 modes on quick scanning monochromators by servo control, experiments are designed and carried out on a inhouse built air bearing spindle. An ACS controller is used to drive the motor, encoder provides the position feedback. A laser interferometer is used to measure the actual angular position of the spindle. Test method: The motor is controlled to move with a set trajectory of sinusoidal signals, and the feedback data from the interferometer and encoder are compared to verify the position and speed. The experiments show that with interferometer calibration, there is only 3\% systematic error in the encoder feedback value. Overall the stepping mode can achieve a resolution of 0.4 arcsecond per step, and the scanning mode can achieve a 50 Hz, 0.08°sine signal tracking. It is possible to get better results by using lighter loads and motors with better performance.