Re: [CAD_CAM_EDM_DRO] Re: CNC Pulse jitter?

Patrick,
No EMC here.
Just windoze/DOS.
I'm using CNCPro and Turbocnc (trial). Both exibit jitter on a Toshiba
Satellite pro and a box with P200.
I found that constant contouring is the major problem (CNCPro).
The real problem is the machine (Dyna Myte 2000) has a 10/1 gear drive
between motor and leadscrew. This leaves the motor with a not quite solid
load and having to run 10 times faster than normal to perform the task.
The steppers are high inductance (16 ohm coils).
Setting the slide gibs tight keeps the resonance at bay for the most part.
If it were mine, I would retrofit to direct drive in a heartbeat.
I also own a Dyna Myte 2400 that I'm upgrading. This also is 10/1 drive.
We'll see how that goes.
RichD

Patrick Mendiuk wrote:

>
> 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