Re: Encoders on stepper motors.

A question along the same lines for the EMC experts:
The encoder counts coming in from the encoders could be a factor of 2
to 10 times the step pulses EMC is issueing becase of the G340
scaling function.
Reading the documentation at NIST these 2 lines in the emc.ini file
are about scaling inputs and outputs.

INPUT_SCALE = 1000 0
The inputs are in encoder counts per inch or mm.

OUTPUT_SCALE = 1.000 0.000
and the outputs are in volts for the DAC.

Any clue if this OUTPUT_SCALE effects the stepper motor output rate?

--- In CAD_CAM_EDM_DRO@y..., "Tom Eldredge" <harmonyt@r...> wrote:
> Dan,
>
> Please comment on this configuration:
>
> EMC outputting step/direction, driving a gecko 340 drive, with the
encoder
> feeding both the gecko drive and your emc/encoder feedback board.
>
> Thanks,
>
> Tom Eldredge
> ----- Original Message -----
> From: Dan Mauch <dmauch@s...>
> To: <CAD_CAM_EDM_DRO@y...>
> Sent: Sunday, March 25, 2001 11:45 AM
> Subject: Re: [CAD_CAM_EDM_DRO] Encoders on stepper motors.
>
>
> > In a properly constructed driver, with the properly set software
> > configuration and a proper machine you shouldn't lose any steps,
however,
> > in addition to what other folks have mentioned there is stepper
motor
> > resonance problems to content with. Just take some steppers and
lay them
> on
> > the bench and do a G02x1.y1.i2 command and watch the motors as the
> > transition from one direction to the other. That is generally
when you
> will
> > note stepper motor resonance. The use of encoders and the
software that
> can
> > utilize encoders helps, if not eliminates this problem. Deskncrt
and EMC
> > both use the Kulaga/Mauch DRO boards to take encoder feedback and
compare
> it
> > to values set in the .ini files. If the error is greater than the
> > zero(error) it tries to speed up the motor and if successful
continues the
> > toolpath. If the error is greater than the set value then the
program stop
> > all three axis and an error message is displayed. If you want to
add
> encoder
> > feedback to your program MC5 then I would be willing to donate an
> assembled
> > board for the task. I guess the source code can be found in EMC
> > Dan
> > -----Original Message-----
> > From: Art Fenerty <fenerty@h...>
> > To: CAD_CAM_EDM_DRO@y... <CAD_CAM_EDM_DRO@y...>
> > Date: Sunday, March 25, 2001 8:31 AM
> > Subject: [CAD_CAM_EDM_DRO] Encoders on stepper motors.
> >
> >
> > >Hi All:
> > >
> > > I might be missing something here. I have heard alot about
encoders on
> > stepper motor systems increasing accuracy. Am I wrong or is the
only
> purpose
> > of an encoder in a stepper
> > >motor system only used in the case of a stepper missing pulses?
If the
> > stepper never misses a pulse, the encoder does not do anything.
The motor
> > can only be positioned to a multiple of its stepping resolution,
right? If
> a
> > motor misses pulses, isn't this an indication of a poorly powered
stepper
> > >system? I get the strange feeling I'm missing something obvious.
> > >
> > >Thanks,
> > >Art
> > >
> > >
> > >[Non-text portions of this message have been removed]
> > >
> > >
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