The term static indicator 　　1, the number of phases: generating different polarities N, S of the magnetic field of the exciting coil number pair. M represents common. 　　2, shot number: the number of pulses required to complete a magnetic field or a periodic change in 　　the conductive state is represented by n, or to the number of pulses the motor is rotated by one tooth pitch angle desired, a four-phase motor, for example, four-phase four-beat mode operation i.e. AB-BC-CD-DA- AB, four-phase eight-shot operation mode i.e. A-AB-B-BC- C-CD-D-DA-A. 　　3, Step angle: corresponding to a pulse signal, the rotor is rotated by an angular displacement represented θ. θ = 360 ° / (number of rotor teeth beat run *), in a conventional two, four-phase, the teeth 50 of the rotor teeth motor, for example. Four-beat step angle θ = 360 ° runtime /(50*4)=1.8 degrees (commonly known as full step), eight beats running step angle θ = 360 ° /(50*8)=0.9 degrees (commonly known as half step). 　　4, the detent torque: the motor in the non-energized state, the lock itself rotor torque (mechanical error caused by a harmonic magnetic field and the tooth profile). 　　5, static torque: Static motor rated voltage is applied, the motor is not rotational movement, the locking torque of the motor shaft. This torque is a measure of the volume of a standard motor, regardless of the driving voltage and the driving power supply. Although static torque proportional to the electromagnetic excitation ampere-turns, and the air gap between the fixed teeth of the rotor about, but excessive use of the air gap is reduced, increasing the excitation ampere-turns is not desirable to increase the static torque, this will cause heat in the motor and mechanical noise. 　　The term dynamic index 　　1, step angle accuracy: each of the stepping motor is rotated by one step angle error of the actual value from the theoretical value. Expressed as a percentage: Error / step angle * 100%. Different operating beats different value within 5%, when four beats operation 　　should run eight beats within 15%. 　　2 out of step: the number of steps during operation of the motor running, not equal to the theoretical number of steps. Called out of step. 　　3, the offset angle: the axis of the rotor teeth of a stator tooth axis offset angle, offset angle motor operation there must be an error generated by the misalignment angle, subdivision driving can not be solved. 　　4, the maximum load starting frequency: driving the motor in some form, voltage and rated current, in the case without the load, the maximum frequency can be direct start. 　　5, the maximum no-load operating frequency: driving the motor in some form, voltage and rated current, the maximum speed of the motor with no load frequency. 　　6, running torque frequency characteristics: the motor have to run under certain test conditions measured output torque curve versus frequency characteristic referred to as operating frequency torque, which the motor is many dynamic curve of the most important, is the fundamental basis for the selected motor. 　　There are other characteristics of frequency characteristics used, starting frequency characteristics. Once selected motor, static torque of the motor is determined, and the dynamic torque is not the case, the dynamic torque of the motor depends on the average current (rather than quiescent current) of the motor is running, the greater the average current, the greater the motor output torque, i.e., the motor the harder the frequency characteristic. For the average current, driving voltage is increased as much as possible, the use of a small inductor motor current is large. 　　7, the resonance point of the motor: a stepping motor have a fixed resonance region, two, four-phase Induction resonance region in general (step angle of 1.8 degrees) or at about 400 pps (step pitch angle is between 180-250pps 0.9 degrees), the motor drive voltage is higher, the motor current is greater, the lighter the load, the smaller the volume of the motor, the resonance region is shifted upwards, and vice versa, the motor output torque is large, and the entire system losing step noise reduction, general working point should be offset more resonance region. 　　8, motor reversing control: when the timing of energizing the motor windings is forward, the energization timing of DA-CD-BC-AB when AB-BC-CD-DA or () or () is reversed.