Re: EMC, freqmod.o, A-axis, .ini settings, oh my!

Tom,

I also feel your pain. I managed to get my TAIG working with the
MicroProto (Sherline) rotary table. Below is in part what I'm using
for the "A" axis. I found input/output scale set to 1000 works for
the stepper as supplied by MicroProto (1.8 Deg/step). I had
problems with the stepper making weird noises when standing, which I
managed to clear up by messing with the deadband. Only complaint:
the A axis step rate is really slow. IMHO freqmod.o is broke...
changing input/output scale shouldn't change step rate, right?

----
[AXIS_3]
TYPE = ANGULAR
UNITS = 1.0
HOME = 0.000
MAX_VELOCITY = 4.0
P = 100.000 ;proportional gain
I = 0.000 ;integral gain
D = 0.000 ;derivative gain
FF0 = 0.000 ;0th order feedforward (position)
FF1 = 0.000 ;1st order feedforward (velocity)
FF2 = 0.000 ;2nd order feedforward (acceleration)
BACKLASH = 0.000 ;backlash
BIAS = 0.000 ;constant bias
MAX_ERROR = 0.000 ;max cumulative error
DEADBAND = 0.0025
CYCLE_TIME = 0.001000
INPUT_SCALE = 1000 0.000
OUTPUT_SCALE = 1000 0.000
----

Take care,
Norm

--- In CAD_CAM_EDM_DRO@y..., Tom Benedict <benedict@a...> wrote:
> On Mon, 19 Aug 2002, j.guenther wrote:
>
> > Welcome to the club!! I have been fighting this problem since
the end
> > of June with no joy. It appears to be a granularity issue, and
the
> > lower the steps per unit the worse it gets. I am going to reload
my
> > EMC setup with BDI 2.16 so I can try it with steppermod.o as I am
> > currently running the BDI-TNG which only works with freqmod.o. I
> > really wish one of the EMC developers would track this down and
fix
> > it. I have thought about running mine with input and output
scale set
> > to 28800, and units set to 1. That way a 90 degree move would be
g0
> > a0.25 which is not the way I want to run it but does work. Sounds
> > like you have a Sherline mill and rotary table. I have the
Sherline
> > 5400 mill and got the cnc rotary table for my 55th birthday.
>
> Wellll... Almost. I've got a Taig mill, and a Sherline rotary
table.
> They actually play very well together. The one catch with the Taig
mill,
> though, is that it doesn't use step/dir, it uses four phase
output. EMC
> doesn't like to do that, so it took some tweaking on freqmod.o to
make it
> work.
>
> The upshot of this is that switching to steppermod.o would involve
> re-hacking the source to make four phase output work. Hopefully
real soon
> now I'll be able to afford the electronics to convert step/dir to
four
> phase output so I can use EMC talking step/dir. That'll also mean
I can
> run the whole beast off a single parallel port. Some day (hopefully
> soon...)
>
> In the mean time I'm trying to get things working. DANG this is
driving
> me nuts!
>
> If I find anything, I'll let you know.
>
> Tom
>
> > > -----Original Message-----
> > > From: Tom Benedict [mailto:benedict@a...]
> > > Sent: Monday, August 19, 2002 11:24 AM
> > > To: CAD_CAM_EDM_DRO@y...
> > > Subject: [CAD_CAM_EDM_DRO] EMC, freqmod.o, A-axis, .ini
settings, oh my!
> > >
> > >
> > > Here's the setup:
> > >
> > > I've got a stepper-based mill that's got four axes. The A axis
is a
> > > rotary table that's bolted to the mill bed so the axis points
parallel to
> > > the X-axis.
> > >
> > > I'm running the latest rev of the BDI, and the motors are set
up to use
> > > freqmod.o.
> > >
> > > I'm trying to tune the .ini parameters for the fourth axis so I
can
> > > address the rotary table in units of degrees. The linear axes
are being
> > > addressed in units of inches.
> > >
> > > I've got 200 step/in motors that are being half-stepped. The
linear axes
> > > have 20TPI leadscrews, so that winds up being 8000 steps/inch.
The rotary
> > > axis has a 1:72 worm gear on it, and uses the same motor as the
linear
> > > axes. So at 5 degrees per revolution of the motor, that's 80
steps per
> > > degree.
> > >
> > > Now for the troubleshooting:
> > >
> > > I've got the linear axes pretty happy. I don't have my .ini
file in front
> > > of me, but I use an INPUT_SCALE and OUTPUT_SCALE of 8000.0 0.0,
> > > LINEAR_UNITS of 0.03937007874016 in [TRAJ] and UNITS of
0.03937007874016
> > > inside each [AXIS_*] section (I'm using inches), and a P of
500.0.
> > >
> > > I've got ANGULAR_UNITS set to 1.0 in [TRAJ] and UNITS set to
1.0 in
> > > [AXIS_3]. With all the other parameters set the same, if
INPUT_SCALE and
> > > OUTPUT_SCALE is set to 8000.0 0.0, the axis works, but it's not
being
> > > addressed in terms of degrees. If I change INPUT_SCALE and
OUTPUT_SCALE
> > > to 80.0 0.0, the axis ceases to function.
> > >
> > > I've tried dinking with this a fair amount. I can marginally
get it
> > > working with the SCALEs set to 800.0 0.0, and address it in
terms of tens
> > > of degrees (so G0 A9.0 would rotate it 90 degrees), but
obviously this
> > > isn't what I'd like it to do.
> > >
> > > Has anyone got a stepper system using freqmod.o to work with a
rotary
> > > axis? Can anyone share a success story that would help me get
this thing
> > > working?
> > >
> > > Any and all help is much appreciated.
> > >
> > > Thanks,
> > >
> > > Tom
> > >
> > >
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> > OFF Topic POSTS: General Machining
> > If you wish to post on unlimited OT subjects goto:
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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........
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