SilentStepStick Speed Limit With Marlin/RAMPS

I will purchase the SilentStepStick from Filastruder because I want very extreme microstepping (1/256), but I have read that the arduino mega 2560 may be too slow to do 1/256 microstepping. But I've also read that the Silent StepStick uses 1/16 microstepping, and uses interpolation to achieve the 1/256. Does using interpolation somehow allow the arduino to have no problems performing the 1/256 function of the SilentStepStick?

My main worry is that I'd have to print very slowly in order to not skip any steps.

When the interpolation happens in the driver chip, then ATmega has nothing to do with it. From outside the chip, it will be a 1/16 microstepping.
Question is, what´s the max. frequency allowed for the step-input of the chip?
-Olaf

Edited 1 time(s). Last edit at 10/08/2015 02:06AM by o_lampe.

Ok, so are you saying that for one single step, the distance travelled will be the same for the normal a4988 1/16 microstep as the 1/256 interpolated microstep? Or will the distance travelled be much shorter?

Since its interpolated the smallest you can do is 16/256

So you set your machine up as it it was a 1/16 micro stepping, so a ATmega is fine.

Yes it still moves the same distance, it just moves quieter (micro stepping does not get you more resolution)

If you want real 1/256 micro stepping your going to need a 32bit controller and real stepper drivers (you still wont get more resolution)

Edited 1 time(s). Last edit at 07/07/2016 10:47PM by Dust.

Well micro stepping DOES get you more resolution normally, right? But with this "interpolated" microstepping, that is not the case, if i understand correctly.

This is the first time I've seen "16/256" so I'm not sure what exactly that means.

Why won't real 1/256 micro stepping achieve more resolution? If it moves a smaller amount each step, isn't that more resolution?

micro stepping only gives you more resolution up to about 1/8 micro stepping, after that its all about running quieter/smother

That's where there is lots of myth and miss information...

if you have say a 200 step stepper with 1/256 micro stepping you do not move an 1/256 of a step each step.

This is where I run out of the correct terminology, but basically the stepper motor will only move when there is sufficient power, at 1/256 there is insufficient power to move, but it is cumulative, so you get 1/256 no moment, 2/256, no movement but eventually at n/256 it gets enough power to move and moves to the correct place it should be at.

I see what you are saying. If the printhead had zero mass, then I think it would move to each of the locations corresponding to the 1/256 resolution positions, but practically speaking, it never achieves it.

But this relates to my original question. Will the silentstepstick do the 1/256 microstepping? Assuming my printhead was massless, could I get the printhead to go to position 3/256, then 4/56, then 5/256, then back to 4/256? Or does the chip automatically go from the 1st of the 256 steps to the 17th of the 256 step automatically (and does this in 16 steps automatically without stopping)?

It does the latter

Eg You send a step command from the controller and the driver sends 16 * 1/256 micro stepping steps to the stepper motors.

All 16 steps, no stopping

Gotchya, makes sense.

Dust's information about stepper motors are quite correct. When I attended the stepper motor control course, it began with with statement:
"Stepper motor moves in full steps. Period. You can control halvish or quarterishish steps too it."

Bad translation but the idea is that each fraction of step is less accurate. What is really wanted is to do a full step with sine wave so that the noise and movement stays in comfortable level. That was one of key points about stepper motors.

The TMC2100 stepper driver which silent stepstick uses has very good datasheet. [www.trinamic.com] After understanding even partially how it controls the motor, you have opinion which has some weight.