Hi,
there was a post a while back where a guy had problems with a 57CNC. It gave the symptoms of having insufficient
kernel speed despite apparently being within spec. If memory serves he ended up getting an ESS which has a max pulse
rate of 4MHz, compared to about 100-125kHz for the 57CNC.
What microstepping regime are you using?.
I would suggest that anything over 8 microsteps per full step (1600 pulse/rev) is unwarranted. Higher regimes offer no
more resolution, I now that sounds contrary to common sense, and I will explain if you absolutely require, but trust me
you get no higher resolution beyond 1/2 step. While higher regimes may offer somewhat more smoothness a regime
of 8 microsteps already offers a good improvement in that regard.
The principle problem with higher microstepping regimes is that for a given rotational speed the number of pulses required to
do one revolution goes up. Therefore your controller CPU/FPGA/DSP has to work that much faster. From what you have described
I think you may be trying to push the 57CNC at or close to its limits which may describe the stuttering.
Craig