Re: [CAD_CAM_EDM_DRO] Low cost Servo drives +/-10V analog....and Camsoft.

----- Original Message -----
From: "dan" <dk1machine@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, October 08, 2003 9:58 AM
Subject: [CAD_CAM_EDM_DRO] Low cost Servo drives +/-10V analog....and
Camsoft.


>
> This question may have been asked hundreds of times....
> Looking for a source of servo drives that accept +/-10Vdc
> analog input. Low cost (of course). The Advanced and Copely's
> are a bit pricy IMHO. Elmo looks interesting, but they wouldn't
> sell me 2 or 3, at reasonable prices. They deal in OEM quantities
> only. Need something in the 80V 10/15A cont. size range.
>
> Thanks
>
> Shawn: How do you like the Camsoft product so far??
>
> dan k
>
>
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Shawncd" <shawncd@p...>
> wrote:
> > Thanks to everyone that responded...
> >
> > Jon,
> > To answer most of your questions here is what I have done so far.
> When I
> > first got the machine home I installed a Advantech industrial
> computer with
> > a Galil DMC 1040 control card. Next I installed Galils servo tuning
> software
> > and Camsofts cnc software. As I tuned the servos for the new system
> I
> > noticed that Z wasn't working, so I diagnosed and found the servo
> amp to be
> > the culprit. After searching all over tarnation for the best price
> on a new
> > / used one. I found one that was identical, except for it has the
> latest
> > revisions. (electrically the board looks a little different from the
> > original) After installing it I noticed that with just axis Z
> plugged in
> > there was silence. No whining noise, as with the other drives. So
> that's
> > when I started questioning the older drives. Maybe the older units
> just
> > sound this way because of the lower frequency. And the newer revised
> > versions have the fix for this nusense noise. Or maybe the other two
> are
> > about to fry as well. Which would make sense because there all the
> same age.
> > Anyway, the other two older drives seem to function and hold
> tolerance. But
> > it started to make me wonder if I should start looking for two more
> drives
> > to replace the others. With hardly any support coming from Servo
> Dynamics
> > this was my next best place for info.
> >
> > Regards
> > Shawn
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Jon Elson" <elson@p...>
> > To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> > Sent: Tuesday, October 07, 2003 9:37 AM
> > Subject: Re: [CAD_CAM_EDM_DRO] Servo Dynamics 1525 servo drive noise
> >
> >
> > >
> > >
> > > shawncd2001 wrote:
> > >
> > > >I recently purchased an older Milltronics Partner mill. This
> > > >particular unit uses the older Servo Dynamics 1525 servo drives.
> > > >I have tuned the drives to where they perform the way I want
> them,
> > > >but there is an ear piercing whine or whistling sonund coming
> from
> > > >the boards. Anybody out there have the same problem? Any ideas on
> a
> > > >fix? Any information would be much appreciated.
> > > >
> > > >
> > > >
> > > Yup, these older drives have very low frequency PWM cycles, and so
> > > produce lots of audible tone. Looking in the book, it says it is
> 16 KHz.
> > > Most people past their 20's can't hear much up there anymore.
> This would
> > > be the same pitch as the horizontal output of a TV set.
> > >
> > > I'm wondering if what you are getting is a subharmonic or
> unrelated
> > > lower frequency than the 16 KHz? Can you make the pitch or
> loudness
> > > of the tone change by moving the axis to a different position, or
> > > manually damping the shafts (motor, encoder, tach) with your
> hands?
> > > Can you make a guess at the frequency of the tone? Are you sure
> it
> > > is coming from the servo amp, and not the motor?
> > >
> > > You might also disconnect or disable all but one amp at a time to
> see
> > > if it is one particular amp, or all of them emit this tone. If
> you can
> > > disconnect the velocity command signal from the CNC control to
> > > the amps, you can see if this is a positioning loop oscillation,
> or
> > > just in the servo amp.
> > >
> > > The Servo Dynamics does have inductors on the output. They appear
> > > to be quite small, so it doesn't seem likely they are emitting
> much
> > > sound. There is a large transformer (T3) on the circuit board. I
> have
> > > only partial schematics of this amp, but I assume this is a DC-DC
> > > converter that provides isolated power to floating circuits in the
> > > amp. It may be running at an abnormally low frequency. Without
> > > diagrams, I can't go much further. You could try wrapping foam
> > > around this transformer, but if it already runs hot, that might
> not
> > > be a good idea.
> > >
> > > Jon
> > >
> > >
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> OFF Topic POSTS: General Machining
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aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
>
>
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