Re: emc with camtronics more help please

Thanks for your help. I was pressed for time last night but with
limited tweaking I was able to get freqmod to work. It was killing
the computer but the few tests I ran seemed to work out right
on .001,.010 and .100 moves(sometimes it would take the display 3+
seconds to update the axis position after the motor stopped). I
already have 196 megs of ram so I don't think that will help. This
morning I was loaned an amd400 I will test tonight or this weekend
with it. I have already loaded emc on it and it is a world of
difference. I had problems on the old machine running the sim with
backplot. The amd400 zooms right through it.

Thanks for all your help,
ben

--- In CAD_CAM_EDM_DRO@y..., Ray <rehenry@u...> wrote:
>
> Ben
>
> With respect to the ini file the things that I'd be sure to do is
set
> accel. MAX_ACCELERATION = 5.0 or less
>
> With 4000 steps per inch I'd also set some deadband. A full step
will get
> you 0.00025 so deadband ought to be a little more than half that.
This
> will stop the emc from driving your steppers between two steps if
the
> commanded value falls in the middle.
>
> With freqmod, you will not get very high speed from it with your
CPU but
> you should get significantly smoother motion. With a P2 processor
> underclocked to 150 and 64 Meg of memory I can run freqmod using
these ini
> settings.
>
> PERIOD = 0.000035
> DEFAULT_VELOCITY = 0.0167
> MAX_VELOCITY = 0.501 (30 ipm)
> DEFAULT_ACCELERATION = 5.0
> MAX_ACCELERATION = 5.0
> INPUT_SCALE = 4000 0
> OUTPUT_SCALE = 4000 0.000
>
> Period might go a little faster on my PC, 0.000031 or so. You you
can
> test this by starting up the emc and seeing how well the mouse
pointer
> follows mouse motion. Some jumps can be expected so set it to
what is
> tolerable for you. (Take account of Franks notion of extra memory
here
> also.) If your PC reboots or dies on startup, you have period set
much to
> small.
>
> Get period where you want it and then test max velocity using
following
> error. Acceleration is the biggest contributor to following
error. If
> you get a following soon after starting an axis reduce this first.
>
> Max velocity might also go a little higher. You can test by
driving your
> longest axis from one end to the other at g0. If you get a
following
> error along the way, max velocity is to fast.
>
> If you do use freqmod, there is a granularity issue at high
speeds. Jumps
> between available frequencies can cause one motion loop to run at
top
> speed while the next motion loop runs at much lower speed. You
will hear
> this as an oscillation from the motor. A stethoscope, or metal rod
> pressed to the motor and to your ear, may help. If you get violent
> changes in speed during a constant velocity move or during a circle
it can
> cause missed steps. If you find such bothersome granularity you
can slow
> the speed or reduce the period.
>
> HTH
>
> Ray
>