The cheap stepper drivers I got with my 6040 CNC machine are pretty garbage
(prone to missing steps, interference, one of them even failed, etc.), so I
was looking into replacing them with far better ones.

Everyone seems to recommend the Gecko stepper drivers because they're
apparently designed well and quite rugged. I was looking at this one:
http://www.geckodrive.com/geckodrive-step-motor-drives/g250x.html but at
$81.00 USD each, they're insanely overpriced. I don't think I could buy one
of those just on the principle of not paying for something that
outrageously priced. So I decided to try and make my own.

There are plenty of schematics available on the internet already, but they
mostly seem to use driver ICs with integrated MOSFETs and are under-powered
for my needs. Then I found this IC: http://www.ti.com/product/drv8711 which
seems to meet all my requirements (micro stepping, external MOSFETs).
However, there's one problem that the Gecko guys claim to solve that I
don't see mentioned by any stepper driver IC manufacturer - midband
resonance compensation. Googling for this doesn't seem to provide any
information on how to solve it yourself, just more ads
<http://www.geckodrive.com/support/step-motor-basics/mid-band-instability.h=
tml>
for Gecko.

Can anyone link me to some information on midband resonance so I can try to
implement a solution myself? Anything would be great, including technical
literature, examples, source code, whatever. The TI DRV8711 seems to
provide all the functionality I need except midband resonance compensation
and I can probably make a good quality driver for around 10-20% of the cost
of an overpriced Gecko.

-- V
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.