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@Arciera,

Attached a gcode sample. A cw and a ccw square. That contains the problem.

Extra torsion turn:
 

No extra torsion turn:
 

The investegation, i printed the clothoid result and take a look at the theta values, and compared them :
** where != means is not.

If clothoid output is like this, fit is ok:

• theta10 Z != 0
• theta 20 XY = 0
• theta 14 Z = 0
• theta 24 XY = 0

If clothoid output is like this, fit is not ok:

• theta10 Z != 0
• theta 20 XY = 0
• theta 14 Z = 0
• theta 24 XY != 0

This let me think about how to solve this. When you have the not ok situation,
you can introduce a tiny error to get the fit off-plane. A off plane fit seems to solves this issue.

So when you add 1e-6 (ultra tiny error) to one off the trimmed line's z-position, it goes off plane. Problem is solved.
So when lines have no intersection, there is no extra torsion turn.

Now i did not test any further. So i hope this is it.

Just so you guys know, I host my own 6.12 PREEMPT_RT sources with all the necessary real-time bits applied, including those for the i915 driver.

github.com/NTULINUX/linux

The 6.12 PREEMPT_RT kernel can lag behind so I manually update my sources to the latest 6.12 mainline kernel more often. My tree also allows building with the -O3 flag (compiler optimization flag) to speed up context switching, a typical culprit for latency spikes.

Just be sure you use the ntulinux/6.12.y-rt branch.

Cheers!

Hi  scotta , I am based in the UK, and I am considering buying a few EC300 boards, flashing them with your amazing firmware and putting them on eBay as a LinuxCNC compatible controller. I think this would ease the way for some people into the LinuxCNC world. Would you have anything against it, or do you know if it is against any license agreements? 

When I was looking for a LinuxCNC compatible controller, the only sensible option I found at the time was the Mesa boards, which are quite expensive and require shipment from the USA to the UK. Also, probably not everyone wants to play with flashing the boards.

Let me know what you think. Thanks!

Please note that the signal in the drive P1 connector is inhibit, so when the input floats the drive is enabled. This means that in order to disable the drive, you need to provide 5V (from P1 #1) to P1 #11.
For a machine like that, I would just wire a single ”enable” to the drives. Either use the existing relay (most likely NC contacts between P1 #1/#11) or reverse the logic in lcnc.
Relay probably better so that drives are disabled when there is no control to the relay.

Yes action buttons are some of the most complicated code.
It does make buttons a little less boring

I have a fundamental problem to follow the discusions on ohmic and/or hypersensing.
It would be great if someone can point to the mistake in my thinking.
All of the pilot arc torch heads I know have an electrode connected to the plasma voltage (negative) and a shield connected to the workpeace.
With a HF pulse on the plasma voltage (relative to the shield / workpeace) the arc is started.
This means that the torch head tip (shield) which is electrically connected to the workpeace can't be used for ohmic sensing because it's alrerady connected to the workpeace.
What's wrong ?

Personally I would close the feed back loop with linear encoders, this will give actual feed back position, with a mesa FPGA this is a very well worn track with plenty of info available. Same for the spindle and encoder that also employs an index.
Sorry I'm too broke to have experience with Ethercat so really can't make a comment that maybe of use.
What kind of lathe are you working with ?
I'm kind of lucky with my Frankenstein Myford ML7\Super 7 in that I have plenty of room for the stepper motors, the only issue was the X axis, but I was able to use 10mm ballscrew and unlike most other lathes the nut is fixed to the carriage casting rather than running under the cross slide.

And for my techno babble mate, lathes conventionally use a XZ setup, Z being the carriage and X being the cross slide.
Also very few lathes, I can't think any that the average Joe would have access to lathes that use linear rails, mostly dove tails for cross slide and top slide and either plain rectangular ways for the bed,eg Myford, rectangular single prism, think 7x14 mini lathe or dual prism for the more industrial type. These are just the ones I can of off the top of my head.

Sorry to the OP for getting a bit off track.