Stepper motor has a technical parameter: no-load starting frequency, that is, the pulse frequency of stepper motor can start normally under no-load condition. If the pulse frequency is higher than the no-load starting frequency, the stepping motor can not start normally, and the phenomenon of step loss or locked rotor may occur. In the case of load, the starting frequency should be lower. If the motor is to rotate at a high speed, there should be a reasonable acceleration process for the pulse frequency, that is, the starting frequency should be lower, and then it should be increased to the desired high frequency according to a certain acceleration (the motor speed should be increased from low speed to high speed).