Re: CNC Pulse jitter?

Rich,
Are you running EMC on that stepper system? I have observed lots of
"strange pulse phenomena" with EMC.
It occurs all over the pulse train and the amount can be MUCH greater than
the 1 -2% that Mariss mentioned.
I tested EMC on a variety of PCs and clock speeds and they all exhibited it
to some extent. What I observed in the pulse train were drastic glitches
along with very small but ever present variations that you'd expect from
RTLinux. I think you're seeing just the small variations mainly with your
analog scope. My damped and undamped test setups were monitoring rotary
encoder outputs as well and motor motion was only effected by the large
glitches. I couldn't see any periodicity to the glitch occurrences, so it
might take some doing to find the source(s) of the problem.

Patrick