Re: Lost Steps (Me again)

--- In CAD_CAM_EDM_DRO@egroups.com, "Matt Shaver" <mshaver@e...>
wrote:

> > From: Kevin P. Martin <kpmartin@t...>
> > >From: Matt Shaver [mailto:mshaver@e...]
> > >But it works fine with different software. I don't disagree

about
what

> you're
> > >saying about the motors, but if different software fixes the

problem, then

> > >the software must be the problem. Isn't it?
> > >
> > It is the combination that is the problem. If you change any one

thing

> > (software, motor driver, or motors), the problem goes away (or

changes).

> > Although the software is the easiest thing to change, that

doesn't
mean

> that's
> > where the blame lies.
> > Unless you feel you must lay blame in order to aim a lawsuit at

the correct

> > party, the fact that you now have a combination that works should

be all

> you
> > need to know. On the other hand, if the "working" software is not
> acceptable for
> > some other reason, it would still be nice to actually

*understand*
the

> problem
> > so you can solve it directly rather than groping around in the

dark.

>
> You're right that this problem is due to a combination of

deficiencies. The

> reason I'm concerned about the software is that I was somewhat

involved in

> the creation and promulgation of the EMC software (and the freqmod

module for

> running stepper motors in particular), that's not working in this
> application. Since Tim's Shoptask works with the EMC software, and

Jerry's

> doesn't, we can reason that there is some difference in the motors

or drivers

> that accounts for this difference. The thing is, Jerry's machine

runs with

> CNCPRO, and Tim's probably will too (although that would be a good

test).

> Even if Jerry's motors and drivers are less capable than Tim's,

CNCPRO is

> capable of delivering a step pulse stream that runs his machine,

while the

> EMC software can't (given the same PC and other hardware). What I am
> searching for is a way to get the EMC software to perform as well

as
, or

> better than, any of the other programs out there and the ability to
> successfully run marginal systems is a test of the software's

quality.

I believe that Tim and I are running the same driver.

I found some literature which came with the original control box for
these motors, (The Control Group). The motors run very smoothly
with that control box. The stuff indicates that the driver is a
chopper, operating at quarter step mode, 40 volts,0.1 to 3 amps.
My driver is a chopper operating at half step mode, puts out 37v and
I've tried currents from .8 to 2.8 amps. But EMC won't run the motors
under 933 steps per second without extremely erratic and noisy
behavior.
CNCPRO had no apparent trouble last night running them at 13.333
steps
per second last night.
All this means nothing to me but hope it helps one of you.

>
> > From: Tim Goldstein <timg@k...>
> > Not disagreeing that the software is part of the problem, but I

don't think

> > it will be the total answer. Sounds to me like the motors are

being run in

> a
> > manner that is marginal (not enough voltage) and the uneven pulse

train

> from
> > EMC is aggravating the condition.
>
> Actually, that's how I read it too. I just can't criticize the

guy's
motors

> if he can get them to work with another program. I'm surprised by

the accel

> rates you're able to use! Maybe if Jerry increases the motor

current, or does

> more tweaking in the .ini file, he'll be able to run with the EMC.
>
> > Matt, what is happening with the idea of using an external pulse

generator

> > for the stepper module. Sure sounds like it would cure this

problem and

> > reduce the required system resources.
>
> Jon Elson's making really good progress on a parallel port

connected
machine

> control peripheral that will offer plug-in modules for quadrature

decoders, D

> to A converters, general purpose digital I/O, and eventually a

programmable

> step pulse generator. He's got the D to A board up and talking to

the PC

> after some difficulty with the sparsely documented EPP mode of

modern

> parallel ports. Using this mode allows for high rate data transfer

and

> deterministic behavior (a problem with USB and Ethernet), without

having to

> open the case of the PC (laptops!!). There's still a lot to do, but

this is a

> major accomplishment. The stepper module will probably be the last

to be

> created. I guess you could say it's in the "conceptual" phase of

development

> ;)
>
> Matt