PIC DRO Dreaming

I like the various PC based DROs. However, I do not have the space to have a
PC and monitor hooked up to each lathe/mill.

A PIC based DRO attatched to LEDs/LCDs would be real nice.

What options are out their?

Paul

----- Original Message -----
From: james owens <wotisname@...>
To: <CAD_CAM_EDM_DRO@onelist.com>
Sent: Monday, March 13, 2000 1:37 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: AMAZING STUFF!


> From: "james owens" <wotisname@...>
>
> Is it possible for you to give more details on this system that you have
used vis a vis PIC DRO and feeding output of the software before the
steppers see it.
>
> The problem I have with lead screw wear is quit common in that the waer is
not uniform over the lenth of the screw because more use is make of the
centre than the ends.
>
>
> ----- Original Message -----
> From: beer@...
> To: CAD_CAM_EDM_DRO@onelist.com
> Sent: Monday, March 13, 2000 5:32 PM
> Subject: [CAD_CAM_EDM_DRO] Re: AMAZING STUFF!
>
>
> From: beer@...
>
> On 12 Mar, CAD_CAM_EDM_DRO@onelist.com wrote:
> > Message: 16
> > Date: Sat, 11 Mar 2000 19:18:39 -0500
> > From: "Matt Shaver" <mshaver@...>
> > Subject: Re: AMAZING STUFF!
> >
> > > From: "Tim Goldstein" <timg@...>
> > >
> > > Terry,
> > > Also, Alan up in Canada was
> > > working on an external PIC based solution a while ago.
>
> > What I wonder is what will the control algorithm do when it senses
that the
> > axis is lagging? In a servo system the amplifiers are commanded to
increase
> > the motor speed. In a stepper system this would imply increasing the
step
> > rate. If the motor has stalled, increasing the step rate won't do any
good.
> > Steve Stallings stopped by today and we discussed this very issue. He
felt
> > that lost steps were most often due to resonance problems and if
you've just
> > lost a few steps because you went over a "resonance bump", then it may
indeed
> > be possible to "catch up".
>
> Matt;
>
> My "solution" - now on the backburner, as a result of
> upgrading to ballscrews - was designed to get around the problems of
> backlash in the leadscrews.
>
> Simply, my system has Step and Dir inputs AND outputs on my homebrew
> DRO. ( A PIC, an LCD and some rotary encoders )
>
> The PC sends S&D to the DRO and the DRO "echos" the S&D info to the
> motor controller.
>
> Should the DRO find two consecutive steps issued with no corresponding
> movement detected, it "pauses" the CNC software. ( CNCPro has this
> feature ) The DRO then issues additional steps ( unbeknownst to CNCPro )
> until suitable movement does occur.
>
> Once the axis is "lined up", the "pause" is released and operation
> continues normally.
>
> This solution seems to me to be innocuous, as the "stopping and
> starting" should only occur at the VERY beginning of a move, and
> really, only at a direction change, so any "messup" of the finish
> should take place at the very beginning of a cut.
>
> It was never my intention to fix a resonance problem by this means. To
> do so seems to me like fixing a poor idle problem on a car by upping
> the idle speed to 4000 RPM - not really a fix.
>
> Resonance should be cured, not just glossed over, methinks. DanM's 1/4
> step controllers should SOLVE a lot of people's problems in this area.
>
> Alan
>
> --
>
> Alan Rothenbush | The Spartans do not ask the number of
the
> Academic Computing Services | enemy, only where they are.
> Simon Fraser University |
> Burnaby, B.C., Canada | Agix of Sparta
>
>
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> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
discussion of shop built systems in the above catagories.
> To Unsubscribe, read archives, change to or from digest.
> Go to: http://www.onelist.com/isregistered.cgi
> Log on, and you will go to Member Center, and you can make changes there.
> For the FAQ, go to http://www.ktmarketing.com/faq.html
> bill,
> List Manager
>
>