Technical Manual for EA350 Analog Pulse Type Servo Driver V101 ➢ About the notching width and depth The notching center frequency when the notch filter width/depth is 0 and the ratio of frequency and bandwidth at the attenuation rate of -3dB are shown in the left table below. The notch filter depth represents input of the center frequency at full cut-off when the set value is 0, or the output/input ratio at full pass when the set value is 100. When represented in dB, numerical values in the right table below can be obtained.
For the notch filter width, the factory setting (2) is generally used ➢ Correspondence between notching width and depth ➢ Precautions for use of the notch filter ◼ The notch filter cannot be used in the torque control mode. ◼ When the notching frequency is set to 5,000, the notch filer is inactive. ◼ For setting the first and the second notch filters, the user may first use the automatic mode to obtain the third and the fourth notch filter, and then copy their parameters. ◼ Though there are 4 notch filters, it is recommended that no more than 2 notch filters be used simultaneously; otherwise vibration may be aggravated.
◼ When adaptive notch filters are used, if vibration cannot be eliminated in a long time, please timely turn off the driver activation function. ➢ Relation between gain adjustment and mechanical rigidity To improve the mechanical rigidity ◼ The machine shall be firmly fixed onto the foundation to avoid shaking. ◼ Highly rigid couplers shall be used. ◼ Broad synchronous belts shall be used and tension of the synchronous belts shall be set within the allowable axial load range of the motor. ◼ Special reduction gears for servo or gears with small clearances shall be used. Low mechanical rigidity represents low inherent vibration (resonance frequency).
◼ Low mechanical rigidity will largely affect gain adjustment of the servo; for a machine of low rigidity, the servo responsiveness shall not be set too high (high gain). Caution ☞ Not all vibration is caused by mechanical resonance. Adjustment of servo gain to its limit may also cause vibration. In this case, improvement can only be made by reducing the gain or shortening the torque command filtering time.
70 Notching width Bandwidth/center frequency 0 0.1 1 0.59 2 0.71 3 0.84 4 1.0 5 1.19 6 1.41 7 1.68 8 2.0 9 2.38 10 2.83 11 3.36 12 4.0 13 4.76 14 5.66 15 6.73 16 8.0 17 9.51 18 11.31 19 13.45 20 16.0 Notching depth Output/input ratio dB 0 0 -∞ 1 0.01 -40 2 0.02 -34 3 0.03 -30.5 4 0.04 -28 5 0.05 -26 6 0.06 -24.4 7 0.07 -23.1 8 0.08 -21.9 9 0.09 -20.9 10 0.1 -20 15 0.15 -16.5 20 0.2 -14 25 0.25 -12 30 0.3 -10.5 35 0.35 -9.1 40 0.4 -8 45 0.45 -6.9 50 0.5 -6 60 0.6 -4.4 70 0.7 -3.1 80 0.8 -1.9 90 0.9 -0.9 100 1 0