Steps per revolution?

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1

Can someone on the pro-team confirm this for me? Looking on the Wiki, I read the following statement from this page: http://www.shapeoko.com/wiki/index.php/About

  • The stepper motors are 400 steps per revolution, but 200 steps/rev will work as well.

Also referring to the GRBL reference, it appears there are (8) microsteps per step, with a net result of 1600 steps per revolution (using 200).

With the Estlcam CNC controls, 1600 steps per rev nets verified machine movements (1" moved = 1" measured in all axes).

I’m curious about the real motor capability… is it really 400 steps per revolution? If so, I can double my precision?

2

The 400 steps thing is an example I believe. I’d thought that the SO3 motors were 200 step units (though maybe this was changed?). The number of steps per revolution going to 40 from the original 20 is a result of the micro-stepping default increasing from 4x to 8x.

3

Thanks @WillAdams

Using the 200 step premise w/8 microsteps nets perfect movement using a 1.575" per revolution displacement. If the motors are really 400 step capable I could halve the displacement and double the accuracy…

4

No, motor steps are a function of design / winding — you can’t change / configure for that after the fact.

Thanks for mentioning this, I’ll have to see about re-wording it.

You could of course, replace the stepper motors w/ higher resolution ones (so long as they have compatible torque and wiring and are the right size). I have 400 step motors on my SO1 and the additional precision is quite nice. Need to rework it to have GT2 belting though.

5

thanks for clarifying… I understand the motor properties and I’m fine with the existing stepper motors. Everything is operational regarding CNC motions/controls with the 200 step/rev and the 1.575" displacement. I won’t be needing more than my net 0.000984375" movement capability for awhile. :grin:

6

Here is a good video on stepper motors that was posted by @atrueresistance :