NEMA 8 stepper motor subdivision control refers to the detailed step-by-step control of the step angle.
For stepping motor, the subdivision function is completely generated by the precise control of the motor phase current by the external drive circuit, which has nothing to do with the specific motor. The subdivision control of the stepping motor is to insert the current synthesis vector with equal size and regular angle, to reduce the angle of the resultant magnetic potential (step angle), to achieve the purpose of the subdivision.
The reason why the stepping motor can realize stepping is that it has been split in the hardware structure (there are different electrified phases on the stator and teeth on the rotor) so that it can rotate not one circle at a time, but step by step according to a fixed angle.
The angle turned in this step is the step angle. Step angle is the inherent property of step motor, and the steep angle of each step motor is fixed after the design.
The step angle of the stepping motor is related to the beat number of motor operation and the number of rotor teeth. θ = 360 / NZ (the calculation formula of the two-phase motor, all examples in this paper take two-phase motor as an example, n is the beat number (generally determined by the number of lines), Z is the number of rotor teeth.)