Re: DRO card and future projects

I would be into giving it a go if you decide to pursue the project.


Tim
[Denver, CO]

> -----Original Message-----
> From: Tom Kulaga [mailto:tkulaga@...]
> Sent: Friday, May 21, 1999 12:00 AM
> To: CAD_CAM_EDM_DRO@onelist.com
> Subject: [CAD_CAM_EDM_DRO] DRO card and future projects
>
>
> From: Tom Kulaga <tkulaga@...>
>
> I guess you've all seen the posts about the DRO card I built. I've
> got an update to the software, adding metric support, cleaning up a
> few things I didn't like, and changing the 4th axis to display in
> degrees instead of linear units. I haven't posted it to the webpage
> yet because I wanted to add backlash compensation first. That's the
> problem.
>
> The big drawback of backlash compensation is that you are forced to
> make sure that all of the slop is cranked to one side of the travel
> before you can zero that axis. If you don't, the computer doesn't
> know where you are inside the backlash zone, and you can't trust the
> numbers on the display.
>
> My question is this: Do those of you who want to use rotary encoders
> have a problem with this? Keep in mind, you won't be able to zero
> the axis until you are certain that you've moved all the way to the
> left or the right of the slop. I can think of more than one occasion
> where this would be *really* annoying, but usually it would just be a
> matter of getting in the habit of watching what you're doing a bit
> more so than normal.
>
> So, did I get that across clear enough? Is it worth it to add this
> feature? I don't want to spend a whole bunch of time working on a
> feature that nobody will want to use, especially since I've got a new
> project I want to start.
>
> Speaking of that new project, I've been following the comments about
> the EMC software (gotta love the free stuff ;) with interest, and got
> to thinking about how I'd go about trying it out here at home. I was
> thinking that buying a motion control card is pretty pricey, and that
> my DRO card makes a great jumping-off point for bigger and better
> things. With a little extra work, and probably an extra 200 bucks, I
> could come up with a 3-axis servo controller card design. It's a
> little more involved, but using PWM for the output signal cleans it up
> nicely, bringing it into the 'definately doable' range, even for
> beginners.
>
> I think that this group could easily write plans to build the card,
> the servo amps, and the guidance you'd need to assemble the lot into
> a really good webpage. I can handle the card OK, but I need to know
> how the card interfaces with the EMC stuff, or if I could provide all
> the register-level programming info to somebody who could write a
> driver or whatever is needed to get things going. I don't yet have
> Linux here at home, so I can't really experiment much. If there's
> interest in this, I'll order Redhat next month.
>
> What do you say, guys? Sound like fun?
>
> -Tom Kulaga
>
>
>
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