Re: [CAD_CAM_EDM_DRO] Re: EMC Contouring Settings/ downloading BDI

Jon:

If you look in the Trajectory.c file there is a section of code which will
correctthsi if you do a setting like the following at the beginning of the
file...

#define A_CHANGE_MAX .1

and the .1 should be a typical ratio of pulses per unit in A to pulses in
Unit to the other axis, it will correct the problem. For eaxmple if the PPI
of the A axis is 50 and the X is 500 then the value is around .1 if X is
5000 then the value is .01
This fixed my problems anyway and the Axis will work properly in this
kind of move.

Good luck,
Art
Master5 Software
http://users.andara.com/~fenerty/master.htm

----- Original Message -----
From: "Jon Elson" <elson@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, February 02, 2002 1:16 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: EMC Contouring Settings/ downloading BDI


> Art Fenerty wrote:
>
> > Hi Jon:
> >
> > The specification may say what it wants, but it is not unusual to have
> > some people useing A to drive a linear rod or actuator or some such
thing.
> > It may be rare, but CNC is growing so fast that the way its being used
is
> > changing. It just didn't seem right to me, that the planner could allow
an
> > axis A move to be pulses at that rate. The software should do a square
sum
> > as Dave says, otherwise the A axis feedrate has to be factored into the
> > small X axis move as a percentage of that axis's move. Try to do the G0X
.1
> > A 180 move under EMC and I suspect you'll get a servo fault or lost
pulses
> > unless the feedrate is very low on the X axis. This should at least be
> > autocorrecting to the maximum frequency of the A axis just in case.
>
> The problem is the trajectory planner actually computes feedrate at the
> cutting surface, and it has no way to know that when a rotary axis is
> added. A definite deficiency. So, I guess it assumed that the A axis
> was always at a radius zero, therefore it could move at max speed
> (or maybe infinite speed) and still be OK. It gets VERY tricky when
> cutter radius compensation is on, because the feedrate is based on the
> moving tangent where the tool touches the work, not the centerline
> of the tool, which is easier to compute.
>
> Jon
>
>
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