Step Motor Driver For Full Step, Half Step Excitation Mode Lab Report

Step Motor Driver For Full Step, Half Step Excitation Mode - Lab Report Example For a bipolar motor, an external device referred to as an H-Bridge can be used to reverse the polarity of the winding and thus the flux. An H-Bridge can also drive a unipolar motor by not connecting the center tap (common) lead or use only one of the windings in the pair. Using the given state machine states and truth tables, the driver circuits for all the three modes of stepper motor excitation were designed and simulated. The following are the diagrams showing the truth table and state machine states with actual motor motion in this design, the no load or constant load accuracy of a 7.5 degree/step motor is within 0.5% noncumulative. It simply implies that the positioning error is the same whether the rotational movement is one step or 1000 steps. Since the step error is noncumulative, it averages itself out to zero within a 4-step sequence, which corresponds to 360 electrical degrees. This causes the transistor collector/emitter junction to conduct. When transistors Q1 and Q3 on, the current flows through the motor coil in the forward or + direction. However, when Q2 and Q4 on, the current to flows through the motor coil in the reverse direction. In the experiment, only half step truth table was presented. However, if you compare the half step and full step tables, it's noticed that all of the full step sequences appear in the half step table, even though not in the same order. This information was useful in the circuit design, especially when writing the codes for the microcontroller.