RE: [CAD_CAM_EDM_DRO] close loop and stalling

I ran deskncrt which used and older version of emc. The feedbback would
help in situtation where stepper motor resonance problem were likely to
occur such as in circlular moves but as other mentioned if the motor was
stalling caused by load or excessive speed then the program would try to
add steps and when the following error became too great (.005) it was
cause the program to halt which would allow the operator to retract the
cutter, correct the problem and perhaps save the part. Surprisingly,
this was actually quite nice to save the stock than to ruin it.
Dan

-----Original Message-----
From: William Scalione [mailto:wscalione@...]
Sent: Friday, May 23, 2003 7:21 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] close loop and stalling


George,

Well from what I have heard from others this is a problem. If the cause
of missed steps is trying to run them too fast or too fast of an
acceleration, having encoder feedback will not help much as EMC will
start spitting out steps at an even faster rate, which will just
compound the problem. Keep in mind that I have not tried encoder
feedback with steppers so I don't really have any first hand knowledge.
Has anyone on the list ever got EMC to run with encoder feedback and the
Kulaga/Mauch card or Jon Elsons PPMC setup.

I think trying to fix a missed step problem with encoder feedback is not
the route to take. A properly set up stepper system should not miss
steps to begin with.

Bill

----- Original Message -----
From: "george_barr" <george_barr@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, May 23, 2003 7:28 PM
Subject: [CAD_CAM_EDM_DRO] close loop and stalling


> I have a question regarding "close loop" systems using stepper motors
> with encoders. The software is EMC. What happens when the motors
> accelerate to fast and stalls using the above setup? Does it stop all

> the motors when it stalls? Or, does it try to correct the motors
> until it arrives at the determined position? I read somewhere that
> with a close loop system you can run the motors as fast as you can and

> let the encoders compensate for slow motors and it will do the routing

> correctly. Can someone explain some of these things?
>
> Thanks,
>



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