Re: [CAD_CAM_EDM_DRO] Runaway servo questions

Ron,
Geckos won't stop in event of a lost encoder (Don't ask:{(

As a matter of fact, there have been times that I was testing and wanted
the servo to run for a particular reason and I just un-plugged the servo,
powered up and it ran like crazy!



At 09:07 PM 12/2/2004, you wrote:

>While running the mill today and thinking about the runaway servo issue
>should an encoder fail. I wondered if an electronic device could be
>designed that mounts between the servo leads and the A/B signal from the
>encoder. It would monitor the pulse train to the servo and the signals
>returning from the encoder. Then be tied into the E-stop circuit of the
>control. If a pulse stream was present and a A/B signal stream was absent
>it would break a connection and make the E-stop circuit drop out. Having
>hard limits at the extremeties of the envelope seem to be the only
>protection available and could result in alot of damage before it ever got
>there. That would be great if something would monitor and trip in a very
>short distance in the event of a lost encoder. Or would a dithering servo
>situation make this impossible? If someone designed one that worked, I'd
>be the first customer. Someone mentioned that Geckos fault after a 128
>step/count discrepancy. I've heard and seen Marriss mention
> the runaway servo issue and dont recall him saying it will stop in a
> short distance. He stresses hard limits at the ends of the travels.
>
>Ron
>
>
>

Bubba

OLDER THAN DIRT
Country Bubba
(Actually the inventor of Country and Bubba)
In God We Trust

LaGrange, GA

http://bellsouthpwp.net/A/r/Arts_home_page/cnc/

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