Re: Axis Stall Problems

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Wayne C. Gramlich"
<Yahoo@G...> wrote:

>
> All:
>
> My Sherline conversion is getting dangerously close to working,
> but I'm running into some problems with axis stalling.

[snip]

> Electronics:
> The electronics I designed myself. Here's a URL that
> has the schematics and everything:
>
> <http://gramlich.net/projects/cnc/motion/rev_d/index.html>
>
> Basically, I use a venerable L298 with heatsink and eight
> 1N5822 (40PIV 3A Schottky Diodes) for each axis.

[snip]

> The problem:
> Each axis can turn slowly under TurboCNC, but after just
> a little acceleration, the axis stalls. This could be
> some sort of resonance issue, but I think it is more likely
> to be problem with my chopper electronics.

[snip]

I'd like to thank everybody who helped figure out my
chopper design error. I have completely redesigned
my 4-axis chopper board and will be sending the Gerber
files off for fabrication in the next day or so. For
those who are interested, here is a URL for the new design:

<http://gramlich.net/projects/cnc/axis4/index.html>

While I was originally leaning towards a basic L297/L298
combination for the redesign, I eventually opted for system
based on a microcontroller, an 8-channel 8-bit DAC, and PWM
circuitry that is done in hardware. This drive should be
capable of full microstepping if I need it.

Again, thanks for all of your help.

-Wayne