On 4/10/2019 11:31 AM, andy pugh wrote:
On Wed, 10 Apr 2019 at 17:12, Danny Miller <dan...@austin.rr.com> wrote:

I have been wondering- can emcmot be separated from the HAl and emctask
and become a true dedicated realtime stage to control the joints?
I suspect not as it stands. This is based on the observation that
motmod is a HAL module.



Shows EMCMOT as a discrete module, and emcmot.c and emcmot.h are supposed to be discrete files.  The motor PWMs and switch IO is under the realtime veil, which is easy to integrate into hw.

I see the shared memory (inherently fast) with EMCTASK, but I doubt ethernet latency would be a dealbreaker.  Correct me if I'm wrong.

I also have this diagram:


which depicts the HAL with servo feedback (not essential as we use steppers) and fault/limit switches going to EMCMOT on a separate port.  That seems functionally identical just a different artistic style.

I'd like to be able to integrate 2.8's circular arc blending trajectory planning into laser cutter and 3d printer control HW. This might eventually mean EMCTASK is also on hardware and Windows machines or anything else with whatever bastard config they happen to have installed can keep it fed with G-code.  The subset of common g-codes may be preferable, you don't need G73 high speed peck drills or G74 left-hand tapping cycle for 3D printers or laser cutters.  I don't think any of the CAM pkgs would even generate subroutines which is best to leave unsupported as it's nonlinear.

Ideally, a bit ambitious, and not entirely within G-code, but I'd like to take a stab at nontrapezoidal acceleration profiles and multiple acceleration models.  This would be useful- in transitioning from the end of a laser cut path into a rapid, it's "as fast as the machine can go" once the beam is off, whereas in starting a cut you may want a smoother stop because of belt stretch causing some oscillation that would persist briefly as the beam turns on.  With lasers you typically want to fullstop briefly at the start and end of every cut, but then why slam it to a rushed G0 stop only to do a G0-to-cold-dwell-then-powerup-dwell-then-go.

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