How to find stepper drivers microstep setting?

I'm working through cailbration for my Prusa Mendel


by Triffid Hunter, it says:

" know what your stepper drivers' microstep is set to. Most set pololus to 16x, GEN3 stepper driver 2.3 is fixed to 2 (half step). "

I have pololu clones based on the A4988 chip, so assumed 16x

How do I find/check the stepper drivers microstep setting?

Also as my steppers are 1.8 deg, does that mean the full microstepping to do the 360 degrees is
360/1.8 = 200 x (say) 16 , i.e. 3200 microsteps to do a full 360 degrees?

Thanks in advance

Mike

On the Pololu drivers (the A4988 is a drop-in for A4983), you control the microstepping by grounding the pins MS1, MS2 and MS3 in different configurations. On RAMPS there are jumpers under the Pololus to control this. Read more here: [reprap.org]

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I'm not sure, but I think StepSticks can only do up to 1/8 microstepping (so 1600 steps per revolution).

You may find this calculator useful for the calibration of XYZ and E: [calculator.josefprusa.cz]

Yes stepsticks only do 1/8 microstepping. I was scratching my head the other day trying to get 1/16 out of some and failing! The MS3 jumper does nothing on them. You will soon know if you have these as everything you print will come out twice the size.

Real Stepsticks do 1/16 and use A4988

Fake stepsticks do 1/8 only and use A4984

Original Pololu's did 1/16 and used A4983

Hope this helps

Edited 1 time(s). Last edit at 03/03/2012 05:56PM by Sublime.

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Guys thanks again.

My RAMPS came pre assembled, with jumpers hidden under the top PCB, so difficult to check without removing the pololu PCBs (anyone for bent pins ?)

martinprice2004 Wrote:
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> Yes stepsticks only do 1/8 microstepping. I was
> scratching my head the other day trying to get
> 1/16 out of some and failing! The MS3 jumper does
> nothing on them. You will soon know if you have
> these as everything you print will come out twice
> the size.

Yes, the proof of the pudding is in the printing.

At the moment I have Z end stop trouble, but as soon as I can I will run a print of say a 10mm cube & check.
However a couple of weeks back I did some checks & it looked ok - if I told it to travel 100mm, it was pretty much spot on, so it looks like I have real stepsticks.

I recently gone to T2.5 timing belts to improve accuracy, so will I expect have to double the number of steps
in the firmware as part of calibration.


Mike

You don't need to double the steps for T2.5 unless you still have 8 tooth T2.5 pulleys, which don't exist AFAIK. If you use 16 tooth T2.5 pulleys you get the same steps per mm as 8 tooth T5 pulleys.

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[www.hydraraptor.blogspot.com]

Thanks Nophead,
Yes the pulleys are 16 tooth. Now you've said it, its clear of course the driver is the rotation of the stepper shaft, irrespective of the number of teeth, a 1.8 degrees step is still a 1.8 degrees step.

Mike