Re: CNC lathe threading?

[Paul <paul-at-bdiemc.fslife.co.uk>]

Hi Ray

Some of the analogue spindle control variables are already read from the ini 
file - Just scaling values for Volts per RPM in forward or reverse directions 
along with an index parameter. I like the idea of having a [SPINDLE n] 
section instead of mixing it up in [EMCIO], this would be a trivial change to 
inispin.cc - Should the spindle/brake on/off delay times also be moved here 
or left in EMCIO ? What about the brake index too ??
Having multiple spindles raises a few questions over programming speeds and 
directions with a single M3 command. This is certainly one for the after 
hours debates.

Whilst full servo control over the spindle would be nice on a lathe, I (as 
are many) am stuck with forward/reverse contactors. Any "electronic gearing" 
strategies would have to slave the motion to the spindle speed. Although a 
PWM speed control would be of use to at least one person. (Another one for 
NAMES).
Synchronizing motion with a spindle index pulse is going to be a challenge, 
particularly at high speeds - I often do thread cutting at 2000 RPM plus...

Regards, Paul.



On Tuesday 11 March 2003 8:56 pm, Ray Henry wrote:
> If we've got the read position figured out then we just need the output
> signals for spindle velocity.  This signal is already available for servo
> users.  For a stepper user, these could simply be an output pin that is
> pulses at something like a normal stepper rate but that continues to run
> so long as the software commands spindle motion.  That way a pair of pins
> could handle spindle direction and step.  I've done this with a servo Gecko
> drive but quickly ran into linear or wrapped rotary limits. (and
> accel/decel problems)
>
> As for the software, I believe that the easiest way to handle this is to
> create a section in the ini named [SPINDLE 0].  Create the necessary
> variables there for any possible setup.  This is where the EMC should look
> for anything related to a spindle.  Variables should include feedback_type
> and location or none for input.  Output vars should include  max_speed and
> output signal type.  There should also be computation stuff there for
> things like reset each rotation vs keep counting.  I named this [SPINDLE 0]
> cause there ought to be allowance for more than one of these.

-- 

"To err is human...to really f*** things up requires the root password."
>From a collection of quotes at http://www.indigo.org/quotes.html