Figure 3 stepping motor drive system of the circuit principle diagram

Figure 3 stepping motor drive system of the circuit principle diagram In 50 Ω external resistor in parallel on a 200 u F capacitance, can improve the injection stepping motor winding current pulse front, improve the stepping motor of high frequency performance.
And fly-wheel diode series 200 Ω resistance can reduce loop discharge time constant, make winding current pulse along the steepening, the current decline time decrescent, also play a role to improve the working performance of the high frequency. 3. Software design The driver according to rotating joint dial the code switch KX, KY different combination of three kinds of ways of working for choice: One way to interrupt mode: P3.5 (INT1) for stepping pulse input, P3.7 for positive &negative pulse input. Epistatic machine (PC machine or SCM) and drive by only two line connected. Two way for serial communication mode: epistatic machine (PC machine or SCM) will control command sent to drive, drive according to the control command to complete the control process.

Three ways for dial the code switch control mode: through the K1 ~ K5 different combination, direct control stepping motor. When power on or press the reset button to KR, AT89C2051 first detection dial the code switch KX, KY state, according to rotary union the different combination of KX, KY, into a different way of working. Given the following way 1 program flow diagram and the source program. In programming, to pay special attention to stepping motor in reversing the processing. In order to make the stepping motor in reversing can smooth transition, and not produce wrong step, should be in every step of setting a sign. Of which 20 h unit of you for stepping motor are turning a sign; 21 h unit you for a reversal mark. In the forward, not only to forward mark a assignment, and at the same time to fiber optic rotary joint reverse zone bit assignment; In the reverse also so. So, when stepping motor commutator, can the last position as a starting point backward movement, to avoid the motor commutator generates wrong step.
Figure 4 mode 1 program block diagram
4. Conclusion The driver by experimental verification can drive 0.5 N.m stepping motor. Will drive part of the resistance, capacitance and fly-wheel diode related parameters to adjust, can drive 1.2 N.m stepping motor. The driver circuit is simple, reliable, the structure is compact, for I/O port line and SCM resource nervous system is particularly applicable.