Re: EMC and 4th axis

Dan Mauch wrote:

> I have my new 4 axis controller (2.5 amps) running very nicely on cncpro and
> desknc. I really would like to use emc also. I figure that the 64stepper.ini
> file would have to be modified and that AXES=4.

Yes. This tells the controller to not enable any other axes. Typically
you have a 3-axis machine with a 4-axis STG board, and this lets the
software know not to even look at the fourth axis, which might default
to both limit switches tripped, etc.

> I would also reason that I
> would have to add the parameters for the 4th axis to the ini file.

Yes, as [AXIS_3] since I start numbering at 0 having grown up in
Abyssinia.

> The question is , with the run file looking for the steppers on 378H for the
> x-y-z and the 4 and possibly 5th axis is on 278H how do you add this to the
> files and last how is the screen changed so that you can see all the axis?

The stepper task hard-codes the first 4 axes direction and clock onto
the D0-D8 pins of whatever address you set as the PARPORT_IO_ADDRESS=XXX
option to insmod in your run script. The next 2 axes direction and clock
are put onto C0-C3 of the same port. Note that C0, C1, are inverted.
This can be ignored since you'll be tweaking the polarities for jogging,
homing, and the input scale in the INI file anyway, so just make them
whatever they have to be.

> Is there a way to designate the additional axis as the A or W axis?
> Or is the screen automatically changed when the additional axis are added
> to the setup files?

In the new GUI (cleverly named "yemc" since it follows "xemc"), the INI
file parameter [TRAJ] COORDINATES is a list of what the labels for the
world frame should be, e.g.,

[TRAJ]
AXES = 4
COORDINATES = X Y Z A

The labels are arbitrary. For the joint frame, the labels are hard-coded
as 0-5, but I'll probably make this settable also.

Note that this still won't work since the EMC only has 3-axis motion
planning and a 3-axis G code interpreter. When this is fixed, the
interpreter will handle X Y Z A B C or X Y Z I J K formats. I don't
recommend using yemc yet, but you can try it out. It worked for me for
the little robot crane machine tool. Problems include how to color the
XYZ display if only joint 0 is homed, since X isn't joint 0 for a robot;
and other things.

--Fred