RE: smdromod.o COMPARED to freqmod.o

[Enrique Sanchez Vela <enrique_sanchez_vela-at-yahoo.com>]

Hello,

   I have a Bridgeport machine with stepper motors, still in the works.
lately I've been wondering why would I require a encoder if the control
loop works in open loop mode, is freqmod used to work in closed loop
with steppers?

  Also why would I need a DRO.

regards,
esv.
ps. pls apoligize my ignorance and help me going thru this, I think it
makes me a good benchmark to emc friendlines.. ;)


--- Tim Goldstein <tgoldstein-at-mlh-services.com> wrote:
> 
> My understanding of smdromod.o is that it is based upon freqmod.o but
> with
> the encoder feedback being actual instead of a mirror of the step
> output. I
> have never tried it, but my concern is that when the stepper is
> falling
> behind sending it more steps (speeding it up) is the entirely wrong
> thing to
> do. I thing it should scale back the feed as a feed rate override and
> then
> add the steps back in.
> 
> Answer to your question is that it should run the same if the motor
> does not
> lag or stall.
> 
> Tim
> [Denver, CO]
> 
> > -----Original Message-----
> > From: Charly Brauer [cbrauer-at-voyager.net]
> > Sent: Wednesday, June 06, 2001 11:43 AM
> > To: Multiple recipients of list
> > Subject: smdromod.o COMPARED to freqmod.o
> > 
> > 
> > 
> > HI emc users
> > 
> > I'm interested in hearing what users think about the comparision of
> > smdromod.o and freqmod.o?  Do the motors run better using 
> > encoder feedback?
> >  Is the algorithm the same as fremod(ie uses PID)?
> > 
> > charly  
> > 
> > 
> 


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