RE: [CAD_CAM_EDM_DRO] "Apparently" I've got interference....

Buffered board definitely.

Make sure that all of your CNC circuitry stays away from the laser
circuitry. I'm talking about power to the PC, power to the motors and
drivers, cable from the PC to the motor drivers and from the motor drivers
to the motors.
Do not run the wires parallel to the laser wiring, run them at right angles.

You might try switching to twisted shielded cable for all of the above.

Have two separate ground points: #1) - for the motors and the computers and
#2) - for the laser. Use a star grounding configuration.

On shielded cable, only ground one end of the shield (if you connect the
ground from your PC through the cable to the ground on your motor
controllers, this will defeat the star grounding for those two devices.

A good short article on ground loops and star grounding is here:

http://www.lh-electric.4t.com/gnd_loop.htm

If you have a couple hours to kill, start here:

http://www.epanorama.net/documents/groundloop/

and follow the links...

You need to get this absolutely nailed before you start powering up the
laser. You could always kill the power when (not if... WHEN) something goes
wrong but it would be better to have all systems working perfectly. Much
less hassle.

Dave

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Stan Lewis
> Sent: Friday, October 06, 2006 4:11 PM
> To: DIY-CNC@yahoogroups.com; CAD_CAM_EDM_DRO@yahoogroups.com;
> mach1mach2cnc@yahoogroups.com; turbocnc@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] "Apparently" I've got interference....
>
>
> Been lurking a long time (while working on my laser cutter)....
>
> Now for my issue. With most of the support equip. powered up
> (vacuum, water
> pump, cooling fan, stepper controller), things start out good
> then get worse for
> jitters....
>
> It makes little or no difference which software (trialing
> both Mach/Turbocnc),
> OS (win98 or xp), or PC (laptop or desktop)... So that leads
> me to believe that
> some stray interference is hoping on the step/dir lines
> inside my cabinet.
>
> Before I start chasing gremlins (or poor design issues),
> which means money, I'd
> rather look at some "known" issues.
>
> 1) I don't currently run a buffered Break-out board.
> Straight wire from PC to
> terminal block then point to point wiring to the stepper
> driver/controller.
> This is my leading thought since the motors go jumpy w/o a pc
> attached due to
> "floating" inputs. Everything calms down if I Power-off/on
> the controllers
> (soon returns).
>
> 2) I could start with just the steppers powered up, then
> sequentially power-up
> the laser components. I'm almost ready to "move" all the
> motion control/beam
> control to a separate cabinet (with separate 5v psu) as there
> are all kinds of
> 'nasty' things in the current cabinet including a 15kv/30ma
> transformer.
>
> 3) I don't have any more "good" guesses.
>
> Just looking for other thoughts.
>
> Stan
>
>
>
>
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