Stepper Microstepping and Current setting Guide


I did reading up about setting the Microstepping modes on Polulo Stepper Controllers (A4982), but im still confused! Can i just enable the microstepping settings or do i need to also set the appropriate current on the driver board? if so how?

Forgive me if this is an obvious question :slight_smile:

You need to do both. Microstepping has nothing to do with setting the current.

No, it isn't obvious. Controlling stepper motors isn't as easy as running a DC motor.

You set the current, then you can change microstepping to whatever you want. Do you understand what microstepping is?

Yes i do, i think, the stepper driver, runs the motor at intermediate current levels to achieve a high step resolution.

im not sure on how to set the current correctly so that the Microstepping works correctly.

You only set the current to what the stepper can handle, the chip handles scaling current back during microsteps.

If it is a 0.6A stepper, set the current to 0.6A or less. Then just set microstepping to what you want/need it to be.

Keep in mind that the Arduino will need to provide more steps to move the same rotation/distance when microstepping is enabled. So if you have 4x microstepping enabled, it'll need to send 4x as many steps to the stepper driver.

Microstepping has nothing to do with setting the current.

This is in principle true but due to the peculiarities of the A4988 motor driver, this comment may be a bit misleading. As Steve said, you must set the current limit to either the design limit of the motor or to something less (and that limit must be less than the maximum current handled by the A4988 driver). In fact, microstepping won't work unless you do this correctly! So, follow the directions in the Pololu documentation carefully.

If you haven't purchased parts yet, buy a stepping motor designed for a maximum coil voltage of 5 volts or higher, maximum coil current of 1 ampere or less and always use separate power supplies for the motor and the Arduino. Be sure to connect all grounds together.

Start with full step operations and make sure you understand how everything works before moving to microstep operation. As a glance through the Pololu forums will show, some motors don't work as planned.

Listen to him, he knows more than I about this.