2.2 KiB
Stepper Motor Modes
A typical stepper motor has two sets of coils, A and B. Applying a current to one or both coils creates a magnetic field that fixes the motor's position. Any changes to the direction and/or magnitude of the current flowing through the coils causes the motor to "step" to a new fixed position. By repeatedly changing the current flow according to a specific pattern the motor can be made to continuously step clockwise or counterclockwise. The specific pattern chosen, known as the step mode in the StepperControl class, determines the size of the step and overall performance of the motor. The speed at which changes to the current flow are made determines the speed at which the motor rotates.
StepperControl supports two different types of step modes: constant-current modes only set the direction of the current flow to either fully on or off, and PWM modes that use a PWM signal to also modulate the magnitude of the current flow.
Constant-Current Stepper Modes
The most basic pattern you can use to drive a stepper motor is to sequentiually flip the direction of a constant current applied to the A and B coils by changing the voltage across their coil wires from positive to negative in the following manner:
Each flip of the direction of the current in one of the coils results in the motor moving a full step. The pattern repeats after four steps, though note it is not symmetrical - running the pattern from left to right ght to leftwill cuad tis not that same as runnign it from riBecause current is always applied to both coils (or phases) of the motor, StepperControl calls this pattern the FULL_STEP_TWO_PHASE mode.