Re: [CAD_CAM_EDM_DRO] Re: Skipping steps, avoiding resonance

Thanks for your comments Bill.
Though your likely not within the exact rules of the List, Your input is
probably extremely helpful to those with noise issues.

Somehow, I envision this 800lb "chopper" a far bigger hazzard when out
of control than a CNC machine! Hey, maybe you can hang a Spindle under
that thing, coupled with GPS.....maybe you can cut something.

I would suggest that you by all means continue to Lurk, Suggesting your
thoughts when you see individuals fighting with those pesky "noise"
issues. I have always followed Shielding rules as best I can. So far, I
can't say I've had a "noise" problem.

Thanks again

gadget_c wrote:

>Hello all,
>
> This is my first post and as a newcomer to this 'sport', I have
>learned much here already just reading. I feel that lurkers are
>probably welcomed but should make themselves known.
>
> The degradation of signal and cross talk between digital as well
>as converted ditital to analog information has been a current study
>of mine. The analog servo system incorporated in the autonomous (800
>lb.) helicopters that we are building is the case in point. Seven
>channels were talking (jittering) when only one signal was present
>to a single analog channel. I found that the unshielded signal
>wiring and common grounding system were to blame, and shielding was
>the primary culprit. We found that the conversion from digital to
>analog was full of spikes that varied with load to one channel and
>would cross-talk into an ajacent conductor and cause the driver to
>go nuts. Filtering was tried but separate grounds and shielding
>alleviated the problem to an extent. But, any conversion such as PWM
>can be a problem with even leaky power supply capacitors, the
>rectifiers can be a source of terrific spikes too - one badly
>leaking one in a bridge... Diodes are noisey anyhow. Use a scope to
>watch various areas of your signal paths - it's amazing what you'll
>see.
>
> Hoping this is not considered off topic, it may help correcting
>some of the stepper and servo motor problems mentioned here. But I'm
>no expert on the subject!
>
>Thanks,
>
> Bill C.
>
>
>
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