Quote Originally Posted by Neale View Post
Quick bit of explanation that might (or might not!) help. Stepper motors usually are built to do 200 steps per rev. This is based on the internal physical layout of the coils and magnetic poles. A simple driver will only allow the motor to move between these "simple" steps. However, most drivers, like the M542, can do something clever in their electronics so instead of energising just one set of coils, they can provide current to both sets of coils but at different levels. Simple case is supply both sets of coils with same current, and the motor will move to a position halfway between the internal poles, so you get a total of 400 steps/rev. By juggling currents, you get "microstepping", where the electronics can move the motor to multiple steps between the 200 mechanical steps. Typical settings are 800 or 1600 microsteps/rev, but this is set purely by the driver and there is nothing on the motor that you change or need to take account of. However, the driver settings generally talk about "x4" or "x8" because whatever motor you use, the number of standard steps/rev is multiplied by this number. We use 200step/rev motors so often that it's easy to forget that there are, for example. 400step/rev motors around, which would give 1600 or 3200 microsteps/rev with the same driver settings.
Many Thanks. i now understand.

Ray