Re: [CAD_CAM_EDM_DRO] Re: faster steppers

Hi Henrik,

Yes, I am using you design of driver boards and they seem to work very well.
I did have a bit of trouble trying to set up the currents with the trim
pots - it was a bit difficult to get a stable state ( Change the running
current and the idle current changes and vice versa ) but they all worked
first time and seem pretty rugged. When I get the machine finished I'll post
some pictures including the driver boards in their old computer case.

I haven't tried driving the steppers through a function generator as I
haven't got one. Before I hooked them up to the computer, I did a little
test of the boards and motors using a very basic 555 timer chip oscillator
to drive them but this didn't really tell me anything except that the boards
functioned OK. I have determined the maximum speed at the moment by trial
and error and altering the ini file in EMC. This is a bit of a learning
curve as I am working in metric unlike most others. However, I now have it
so that, on a G0 command, the motor will drive the axis smoothly and cleanly
as quickly as possible without stalling ( I actually got it up to about 570
r.p.m. but it wasn't rock solid and so I backed it off to 540 where it is
happier. Even though the motors are not too powerfull, I can't stop the
carriage with my hand at this speed so it should be OK.

Ian
--
Ian W. Wright
Sheffield UK
www.iw63.freeserve.co.uk

----- Original Message -----
From: "Henrik Olsson" <henrik-olsson@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
I _think_ Ian is using my schematics
> and boardlayout for his drives..... Ian?
> So if Ian IS using the design I sent him he should be able to compare the
> results, at least to some extendt.
>
> Ian,
> I'm glad to hear you got that speed up! I didn't think of the
software-side
> of the problem. If you have a functiongenerator or pulsegenerator you can
> connect that and see if you can go even faster. I have noticed, when
running
> the motors with my functiongenerator, that it makes alot of difference how
> fast I 'accelarate' - to fast OR to slow makes the motor stall. So I can't
> say I can run 10000 half-steps/sec reliable. As you can tell I'm FAR from
a
> semi-pro when it comes to steppers and there drives but atleast I got it
> running and keep on learning every day.
> Good luck!!
>
> /Henrik Olsson.
>
> Oh..if anybody else is interested in the design I'll be glad to share.
>
> > Henrik, List,
> > Although the 297/298 chips are ubiquitous(everywhere), the drivers
> > made with them are NOT ALL the same. This chip set responds well to
> > good design and layout, and PUNISHES poor layout/design! So,
> > comparing different mfrs. 297/298 bds is not often apples/apples...
> > Hope this helps.
> > Ballendo
> > P.S. So Henrik, if those ARE 297/298 boards, you must be pretty
> > good :-)
>
>
>
> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
discussion of shop built systems, for CAD, CAM, EDM, and DRO.
>
> Addresses:
> Post message: CAD_CAM_EDM_DRO@yahoogroups.com
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...
> Moderator: jmelson@... timg@... [Moderator]
> URL to this page: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
> bill,
> List Manager
>
> FAQ: http://www.ktmarketing.com/faq.html
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>