Re: [CAD_CAM_EDM_DRO] J R Kerr

I have used the JR Kerr system in a lathe I retrofitted, with his enc-step
adapter. I had to make an adapter to get +- 10 volts out of it, and I had
some other problems with power up sequencing, which Mr. Kerr helped me
solve. I could not find any info. warning about the problem, and the system
hung up while I was installing it 12 hours away from home (each way). I was
pretty distressed that I would probably have to go back down there and
troubleshoot the problem, because JR. Kerr does not give out his phone
number, and your only support is through email. For me this was the last
straw. I did not know about the Gecko drive, but my experience thus far
with Gecko (Marris) is that you could never find better support for any
product than Marris provides, so until I run into a barrier, I'm with Gecko.
I am confident that he will increase the voltage limitation on his Gecko
drives as well, so I expect to see more good things from him. I would also
note that Marris's PID is achieved through Analog means, while JR Kerrs is
done digitally. I forget what the through put comparrison is, but I'll bet
Marris's method is faster.

Tom Eldredge

----- Original Message -----
From: Andy Olney <andy@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, February 17, 2001 11:56 AM
Subject: RE: [CAD_CAM_EDM_DRO] J R Kerr


> I have a set of his boards and have 2 axis working on my Grizzly G1004.
Due
> to my design decisions (motors too small etc.), not problems with the JR
> Kerr stuff, I am planning to move to the Gekko G340 and servo motors.
>
> His system is a great example of the smart box in the smart vs dumb box
> debate we had a while ago. It has a built in PID servo loop, command set,
> communications protocol etc. It has the limitation that the cheap commonly
> availible control programs won't work with it without some programming. He
> has lots of open source programming help availible and also a G code
> interpreter that works with his CMC chips works but is fairly basic.
>
> At this point, I think that for a CNC machine the Gekko drives and
> servomotors will provide a faster, cheaper and better path to a working
> machine. Andy
>
> -----Original Message-----
> From: Tom Enterline [mailto:cadcam@...]
> Sent: Saturday, February 17, 2001 9:31 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] J R Kerr
>
>
> Hi,
>
> With all the talk about the Gecko drives and/or homebrewing a PIC
> solution, I'm curious why there's no discussion of the J R Kerr systems
> (www.jrkerr.com) They sound pretty interesting, e.g. the PIC-SERVO 3PH
> (7A, 48V, $240). Do they work? Does anybody have experience with them? I
> know I saw them mentioned on somebody's list of links.
>
>
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> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
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