RE: [CAD_CAM_EDM_DRO] Re: CNC Pulse jitter?

Rich:

You might want to try running with an empty CONFIG.SYS file and see if you
still experience your stutter. If not, you've got a driver that's taking
more time during an interrupt tna it should. I had a problem using Novell
DOS-7 (MS-DOS workbetter) and found that the EMM386.EXE file was causing the
problem. Once I removed the driver while I was running a CNC program, the
pulse train got quite a bit more stable.

-- Jerry

|
|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
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