Re: emc spindle

[Jon Elson <jmelson-at-artsci.wustl.edu>]

Ray Henry wrote:

> I'll vote for this.  I need +-10v and closed loop with a quadrature
> encoder.  The interpreter handles a spindle speed command.  I'd prefer
> treating it just like another axis in the ini with a new type definition
> - spindle - to make it distinct from the rolled linear definition - angular
> that we use now.

Right, for complete control on hard tapping and for turning center
applications, you'd want to be able to tell the spindle to go CW
12 turns and then stop, and then go 12 turns CCW.  I suspect EMC
lacks some  of the hooks in the interpreter to allow you to specify
either spindle position or velocity.  If you made the spindle a normal
axis, then you'd have to tell it to go so many turns, and it would have
to coordinate with the other axes.  Maybe it could be set up so that
a spindle start M command would mean for constant velocity
(unless that turning center G code for constant surface speed was set)
and if you addressed the spindle with something like a C command
then it would become a positioning servo, and proceed for some
number of turns at a programmed velocity.

Otherwise, I think some kind of extension to the RS-274 standard
commands might be needed to 'have it both ways'.

Jon