Re: Allegro 3977SED questions

Where to get encoders?


For linear scales, these use quadrature devices, so Chinese scales
are pretty much out. If you hit the Shumatech group, Tim of Linear
Measuring Systems, Inc (Anaheim, CA) is the US importer of "Jenix"
scales. These are really very nice quality...every bit as nice as
you get from Acu-Rite etc. but for FAR less$$$.

There is also US Digital in Vancouver, WA to look at for other types
of encoders etc. And of course, Agilent-HP has a wide range of
encoders you can mount to steppers, servos, rheostats etc.

Tom


--- In CAD_CAM_EDM_DRO@yahoogroups.com, Vlad Krupin <vlad.cnc@g...>
wrote:

>
> Hi Ron,
>
> You said that you added encoders. That sounds like a great idea.

The

> question is... where do you get the encoders themselves? I checked

out your

> site, and I see the boards, all the circuitry, cables, etc. But

where do you

> get the actual encoder units from? I assume they'd be some small

units that

> you can just mount on any nema23 motor shaft, right?
>
>
> Michael - I found that I mostly needed the torque for rapid

movements, and

> for being able to reduce backlash to a minimum without stalling,

not so much

> because I was cutting a hard medium as opposed to foam. I also

tried to see

> if I could do it as cheaply as possible. Two years later, I must

say that

> making controllers to drive your motors (especially designing them

from

> scratch) is not necessarily the cheapest thing out there. But you

do get to

> learn a lot about PCB design and manufacturing in the process!

Lots of fun

> and overall enjoyable experience!
>
> Vlad
>
> On 12/23/05, R Rogers <rogersmach@y...> wrote:
> >
> > The HobbyCNC (www.hobbycnc.com ) system is going to be tough to

beat. I

> > bought one of the 4 axis systems, had it assembled and running

in a few

> > hours. It's a very nice unit with resolution/microstepping as

fine as 3200

> > steps per motor rev. Chopper circuit. The Nema 23 motors I got

with it seem

> > very good quality also. Very powerful for their size. I even

added encoders

> > and made it a closed loop system with Mach3. No lost position.
> >
> > I sell the encoder board that makes this possible:
> >
> > www.rogersmachine.net
> >
> > Ron
> >
> > lomcevaktumble <lomcevaktumble@y...> wrote:
> > Vlad -
> > At the moment the plans are to build a cheap-o 4 axis foam

cutter.

> > I'm looking at motors in the 60 - 120 oz.in. range. Fortunately

not

> > too power hungry! I want to do everything as inexpensively as
> > possible just to see if I can do it! If everything goes well and

I

> > feel confident I'll probably move on to something much more
> > powerful! I'm not above converting everything I own into a CNC

based

> > machine!!!! And a mill would be super fun! Theoretically- with
> > enough CNC equipment- I'd never have to go shopping again. I'll

just

> > make everything in my garage!
> > Your ebaying Kung-Fu skills must be much better than mine, I've
> > never been able to find any steppers that I liked. They're

usually

> > some mixed lot of one decent one and 3 that look like something

left

> > over from the cuban missile crisis. I've resorted to new motor
> > shopping from automation direct...the prices aren't too bad for

new

> > equipment.
> > I do value your input...because it lets me know the limitations

of

> > what I'm doing. I now know that I'm not going to be doing much
> > beyond foam cutting with this driver!
> >
> > Happy Holidays
> >
> > Michael
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, Vlad Krupin
> > wrote:
> > >
> > > Sorry, I must've misunderstood what you were trying to

acheive. If

> > you are
> > > looking for something that can be put together quickly and

drive a

> > > 1.7-2.0Amotor at 20-30 volts, then 3977 is a great choice.

Simple

> > > board design, few
> > > external components - it is great. I tried it, and I liked it

in

> > general. I
> > > just had a hard time finding stepper motors that did not want

4-

> > 5A... And
> > > much higher voltage... Maybe my ebaying kung-fu skills are
> > subpar :) So,
> > > that started me down the road to designing something that could
> > drive the
> > > motors that I bought, and the experience was just as much fun

as

> > converting
> > > the mill to CNC in the first place. Since I am no electronics
> > expert either,
> > > it did take a looong time (still learning). I thought you were
> > trying to do
> > > the same.
> > >
> > > Good luck on your project!
> > >
> > > Vlad
> > >
> > > On 12/22/05, lomcevaktumble wrote:
> > > >
> > > > Vlad -
> > > > The 3977 seems to fit what I need it to do pretty well. The
> > > > steppers I'm looking at are in the 1.7 - 2.0 Amp range. The
> > machine
> > > > I'll be building won't need very heavy stepper motors.
> > > > I picked the 3977 because it was recommended and its seems

pretty

> > > > simple. I'm not an expert with electronics and I need

something

> > that
> > > > can be slapped together by me. I also need something fairly
> > quickly.
> > > > Do you have any recommendations for something that might fit
> > those
> > > > parameters? I'm always open to looking at something else.

And of

> > > > course if I ever build a machine that needs more powerful

motors

> > > > I'll have to leave the 3977 chip for something else.
> > > >
> > > > Thanks for all the tips and info everybody.
> > > >
> > > > Michael
> > > >
> > >
> > > --
> > > Vlad's shop
> > > http://www.krupin.net/serendipity/index.php?/categories/2-
> > metalworking
> > >
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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
> >
> >
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> --
> Vlad's shop
> http://www.krupin.net/serendipity/index.php?/categories/2-

metalworking

>
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