Re: [CAD_CAM_EDM_DRO] Re: Digital DC Variable Speed Drive for spindle control

First, for a DC drive to run both directions (and to provide braking)
without contactors it must be a regenerative drive.

Step commands are frequency. A normal stepper driver interprets these to
drive a motor. You can drive an inverter or DC drive the same way via a
frequency input (or F to V converter), but they will not have the
positional accuracy that is inherent in a stepper or servo system.

Direction can be thought of as a simple switch, either on or off. Simply
configure one of your digital inputs for CW/CCW operation. Download the
drive manual or the drive configuration software (free!) for an explanation.

---OR---

Run the drive off your serial communications port. Talk to Carotron about
parameters. Be sure to have a failsafe hardwired method of shutting the
drive down in the event of communications errors or failure (this goes for
any system that uses *any* type of communications link).

You cannot use the encoder as it is presently mounted for motor
feedback. Use the tach instead, or move the encoder to the motor
shaft. Tach or encoder feedback will provide 0.01% speed
regulation. Armature feedback will provide 1%, that may be adequate for
your application.

As always, the KISS principle applies.

Don't worry about asking questions!

Bryan Moody







At 05:55 AM 1/26/04, you wrote:

>Hi Bryan,
>
>Thanks for the input I took a look at the Carotron site and I liked
>what I saw, a couple of points I would like your opinion about:
>- When you say the drive will accept frequency inputs as standard do
>you mean like step pulses from mach2?
>- If so, which way would you go, step & Dir, or serial
>communication?? I asked Art about mach2 supporting serial
>communication, and he said mach2 can be configured to send serial
>commands but not receive.
>- In my lathe setup, I have a tacho attached to the motor, and an
>encoder attached to the spindle (1024) PPR, and there is a 3 speed
>gearbox between motor and spindle, which way to go for feed back,
>tacho or encoder.
>
>I'm sorry I'm asking all sort of questions, as I'm doing this for
>the first time.
>
>Mina F.
>
>
>--- In CAD_CAM_EDM_DRO@yahoogroups.com, fiteboss@y... wrote:
> > Control Techniques makes good drives, if (IMO) a little bit
>overpriced.
> >
> > For DC drives, I really, Really like Carotron. Good pricing, great
> > technical support. They aren't as pretty as some others, but they
>get the
> > job done, day in and day out. Mike Jenkins and his crew make an
>excellent
> > product. I've got quite a few installed in some severe industrial
> > environments, and I've *never* had a failure. Amazing.
> >
> > The ElitePro drive will accept frequency inputs as standard, as
>well as
> > 1024PPR quadrature feedback. Configure one of your 7 digital
>inputs as
> > direction. Or use the supplied RS232 or 422 communications ports.
>Speed
> > regulation with encoder feedback is +0.01%
> > http://www.carotron.com
> >
> > BTW, DC drives are not inverters.
> >
> > Bryan Moody
> > Not affiliated with Carotron!
> > Just a very satisfied systems integrator.
> >
> >
> >
> >
> > At 05:51 PM 1/24/04, you wrote:
> > >Gentlemen,
> > >
> > >I'm in the process of changing the old Fanuc controller of a
>medium size bed
> > >lathe to a new control using mach2 and Geckos.
> > >I already setup my Z&X axis, and they are working fine, now I'm
>getting to
> > >the part of spindle speed control, the spindle motor is a 11 Kw
>BBC
> > >DC motor, which came with its old speed controller which I'm
>scrapping.
> > >I'm thinking of buying a new digital DC variable speed drive
>(inverter) for
> > >the motor like the one in the URL below:
> >
> >http://www.controltechniques.co.uk/products/mentor_intro.htm#Benefit
>s
> > > I know it's a bit expensive, but I'm planning to use the lathe
>for
> > >production work, now I was wondering of the way to control the
>speed drive
> > >from mach2:
> > >
> > >- Can I send step & Dir pulses to the speed drive as it has
>digital inputs.
> > >- I have a 1024 PPR encoder attached to the spindle, do I send
>the encoder
> > >pulses to the speed controller for feed back.
> > >- If so, can I rely on the speed controller to keep a constant
>speed, for
> > >threading operations, or do I have to take an index pulse to
>mach2 to do
> > >threading.
> > >- I think mach2 does not support serial communication to speed
>drives, am I
> > >correct.
> > >
> > >- If non of the above is feasible, what other options do I have to
> > >communicate between mach2 and speed drives?
> > >
> > >Please advise,
> > >
> > >Mina F.
> > >
> > >P.S. I apologize for multiple group posting.
> > >
> > >
> > >
> > >
> > >
> > >Addresses:
> > >FAQ: http://www.ktmarketing.com/faq.html
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> > >
> > >OFF Topic POSTS: General Machining
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> > >
> > >http://groups.yahoo.com/group/jobshophomeshop I consider this
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> > >
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>
>Addresses:
>FAQ: http://www.ktmarketing.com/faq.html
>FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
>Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
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>timg@...
>Moderator: pentam@... indigo_red@...
>davemucha@... [Moderators]
>URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
>OFF Topic POSTS: General Machining
>If you wish to post on unlimited OT subjects
>goto: 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
>
>
>
>Yahoo! Groups Links
>
>To visit your group on the web, go to:
> http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/
>
>To unsubscribe from this group, send an email to:
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