Boards such as these operate up to 35vdc and are settable for up to 2.5amps, The PWM technology ensures that the maximum POWER to the particular winding is not exceeded, the characteristics of a stepper motor change with step rate speed, so the PWM adjusts the Average power for a constant so that maximum torque is possible throughout the speed range, The on board setting is for maximum current that your motor is rated at.
Al
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.