Re: [CAD_CAM_EDM_DRO] Stepper Motor and Cable Shielding. Any tips?

Tom,

One thing you might test is running VERY low accelerations. I have high
quality Sanyo-Denki NEMA42 steppers driven by G210 Geckos on my mill and
have consistently lost steps on long 3D programs with lots of contours
etc. I've tried microstepping, no micropstepping, long step pulses,
short step pulses etc. same problem. All my cables are shielded, things
are grounded etc. etc. still problems. I'm using Flashcut, but I also
tried Indexer LPT and G-Code Controller with the same result so I know
it isn't my controller.

I recently tried running extremely low accelerations and the problem
almost completely went away. I still don'tunderstand why I'm losing
steps but as a result of my last test, I am currently in the process of
going from open loop steppers to closed loop servos (purchased off eBay)
and am (extremely) hopeful that this change will solve my problems. I
will post the results of my tests.

The only other thing I might suggest you check is the power supply
wiring. If your PSU can't provide the peak currents your controller and
motor is drawing - that could also be a factor. Low current = low torque.

Hope this helps.

Cheers, Peter


kaynrc wrote:

> In case you follow more groups than just this, I have also posted
> this in the Master5 group, with few replies thus far.
>
> I have a semi-sick stepper system, with Dan Mauch's 5 amp boards and
> Master5 as the software so far. (I'd like to stay with that one). The
> motors are new, 521 oz-inch also from Camtronics.
>
> I lost lots of steps on a bench test, whether I add resistance to the
> motor shafts or not (by hand). So I am losing steps somewhere, no
> matter how I adjust the feedrates or pulses per inch etc.
>
> I'm starting to suspect RFI or EMI is important and hurting my
> system, even if there are other causes on top of that.
>
> Can someone point out any shielding tips with respect to:
>
> 1. The parallel port cable (I have already bought some shielded-
> twisted paired wires, so I'll be making a cable, but what about
> grounding? Ground at one end only, and to the computer casing????)
>
> 2. The motors. Do they give off a hailstorm of RFI from the wires?
>
> 3. The wires from the breakout board to driver boards. Shield these??
>
> 4. Ground my case which holds the 3 drivers? Grounded also to the PC
> casing??
>
> 5. Anything I may have missed or gotten totally wrong, feel free to
> add in. I have, by the way, done a search on shielding in this and
> other groups, and gotten a good beginning picture. But I don't feel
> that I have the full picture yet. OK, I'm slow !
>
> Thanks for any feedback. Tom.
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>
> 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 as 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........

>
> Post messages: 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 group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
> bill,
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to

http://docs.yahoo.com/info/terms/

>
>
>
>