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I’m also looking for a real machine for extended testing of the multi-channel system. It does not matter whether the machine still has the original drives.

Are you located in the US?  If so, I can help you find/obtain a really cheap machine for testing.  HGR Surplus typically has a number of obsolete swiss-type lathes for sale that can be had for essentially scrap value.

I'm only about an hour from HGR and can get eyes on any machine candidates if you're serious about acquiring hardware for testing.
 

If anyone is interested in testing the system, contributing, or discussing the architecture, I’d be happy to share more details, screenshots and videos.

I don't have a machine that's a perfect candidate for testing, but I do have a subspindle gang-tool lathe with a separate parting slide mounted to the headstock.  Both the slide - configured as either a V or X axis using switchkins - and the subspindle could be re-configured in a separate channel if that would be of any use to you.

Just to clarify, my sub is mounted on the X-slide and is intended to be used with tools (eventually) mounted next to the headstock for back-work. 

My operations are (will be) sequential, other than the parting and sub hand-off; it's not the textbook example of multi-channel like a swiss or sliding headstock.

I am not skilled enough to really help with coding, but if you can walk me through a configuration and GUI setup I'd be happy to try something.  Servos are step/dir with glass scale feedback.

And another thing... I struggled with LCNC's limitations on axis letters.  While my main spindle is also the C-axis, my sub is not defined as an axis despite being mechanically capable of it (servo driven). I'm not aware of any way to add axes beyond the standard 9 which also participate in the trajectory planner (i.e. not 'extra-joints').  I would rally have liked to name the sub "C2" or similar.  In your post you indicated 'C1' and 'C2' and that axes could be shifted between channels, but it's not clear how axes beyond the usual letters are named or handled.  I'd be interested in how you're addressing duplicate axis names - a basic swiss lathe capable of simultaneous sub work would need C1, X1, Z1 (main) and C2, X2, Z2 (sub).

As @tommylight said, this would be a monumental addition to LCNC.

djdelorie, the error idea is good, and it's the missing half of this. With a radius reference available, the state space for a rotary cutting move in G94 becomes:

G93 active: fine, inverse time.
G94 with a radius set (INI default or a G-code word): fine, surface feed.
G94 with no radius anywhere: today this silently runs deg/min, your "stupidly slow" case.

An opt-in INI guard makes state 3 a hard error instead of a slow wreck: "rotary feed move with no radius reference, add G93 or set a feed radius". Loud failure with the fix in the message, instead of finding out by watching the machine crawl. Every rotary machine then either runs a correct feed or refuses to run.

The guard alone is worth having even without the rest, since it catches the forgotten-G93 case you described, which the feed feature by itself doesn't. Cheap to implement, breaks nothing, machine builder opts in.
On "anything new is work and learning": agreed, which is why I'd keep the operator-facing part to one G-code word and let everything else default to today's behavior. The guard is the one piece aimed at operators, and its whole job is to say "stop, your program is missing something" instead of teaching them a new mode.

tuxcnc, on the Mach3 comparison I think you're aiming at the wrong part. The thing that's bad in Mach3's rotation radius DRO isn't the concept, it's that the radius is a value the operator types per stock and nothing in the program records it. That critique I fully agree with, and it's exactly why a G/M word carrying the radius in the file is the right mechanism, as you said: one file, reusable per diameter in a single program, unused by anyone who doesn't want it. Nothing to argue about there.

Where I disagree is "the same g-code should execute the same way on different machines". That was never true, in LinuxCNC or anywhere else. WRAPPED_ROTARY in the INI already changes what G0 A400 does. The default G64 tolerance, the G20/G21 default, startup codes, and above all the kinematics the machine builder picks, all change how the same file executes. G-code describes a toolpath relative to a machine definition; cross-machine portability has always been the post-processor's job, not the interpreter's. An opt-in INI value that no existing config sets is the same kind of contract as those knobs: unset means behavior identical to today, zero risk to twenty-year-old programs.

And it isn't Mach3 lineage. Siemens has FGREF for exactly this, settable from the program, which is an argument for your G-code form. Fanuc goes further in the direction you dislike: a parameter bit switches rotary feed from deg/min to length/min outright (1404#1 RFD, if I remember the number right). So both ends exist in serious industrial controls.

On "questions like who would like it are the wrong questions": I think asking is precisely the right first step. A project like this stays alive for 20 years because the people building it keep an ear on what users actually need, and because users see that asking can lead somewhere. "Devs build whatever comes to mind, users take it or leave it" is the model that slowly empties a user base. A quick census before sinking weeks into a feature isn't design-by-committee, it's just checking that the work lands with someone. Nobody is bound by the answers; I'll weigh the design on its merits, this thread included.
Net result of the thread so far, the way I read it: G93 covers the CAM crowd, hand-writers would take a G-code word for the radius, and whatever lands must not change behavior on any existing config. That's a useful outcome for a few days of asking.

I will suggest another option... An INI setting that causes any A motion other than a rapid to be an error, in G94 mode, or perhaps a pop-up warning.
A G94.1 mode for "It's G94 but use the X/Y/Z in the INI as the rotary center for calculations" would be nice, but anything "new" is work and learning for operators.
 

Danke Juergen, wir werden es uns ansehen.

Hi @dbtayl. Thank you for the observations. Here are some thoughts on the ODD and Bad.

The Odd

1) Both Z43 and Mouse behaviour can be set in preferences.
2) Updates will be available for upto 24 months from a product launch. After that the product works as is forever. We expect to release a new product that keeps up with changes in OS and tech. You can continue using the old one forever.
3) We use Paddle - a UK based MOR. We are adding Paypal directly to the options soon to make it easier.
4) Let us know if you face any specific bugs and we can address it. We have a community hub website. We track all bugs live there and currently the queue is clean.

The Bad

1) Yes you can, the op specific parameters allow you to choose between sihouette and Bounding box
2) We will refine the strategy in the coming weeks. Thank you for the input
3) Understood, this is a likely bug where the face picker may be masking the edge picker. We will investigate and fix
4) Ramps for pocket is scheduled as a 1.0.10 update. About 3 weeks out from today.
5) Yes, we limited it to the operations we thought needed it. Can you kindly tell us which other ops you find it useful and missing
6) Our website states that collision detection is available only for 3D Ops and Complex Rotary Ops. Never oversold. If some literature miscommunicated the same, kindly let us know.
7) We have pick start in the op config section for the ops that we thought needed it. Once again, if you can help us identify other ops you think qualify for it, we'd be happy to take a look at it.

Your comment on AFR being a hit or miss is especially worrying to us as this is the first time we received this as feedback. All other customers are very happy with it and have not reported any false positives yet. Can you tell us how bad the miss was?

In process stock is scheduled for 1.0.12, which is about 5 weeks off.

Overall we thank you for an unbiased critical view of our app and we are certain we can improve all of these to meet your expectations.

 

First of all, GIGO, i.e. processing incorrect data, gives incorrect results.
You can also say that if you ask the wrong question, all the answers will be wrong...
Questions like who would like to do it and whether to do it are the wrong questions, especially when asking a small and non-representative group of a few active users of this forum.

The real question is: HOW NOT TO DO THIS?

And here we know the right answer - NOT like in Mach3.
Mach3 is commercial software, which means that nothing is done to make it work good, but to make the users like it, because the company's income depends on the users' satisfaction.

It works differently in free software - if someone has the time and inclination, they add a new utility, and if someone doesn't like it, they don't use it.
The only problem here is not to break anything and not to let a program with a twenty-year history suddenly start working in a way that is unpredictable for the user.

But let's get back to Mach3.
I don't have the time or inclination to look for better examples, but what I quickly found is completely enough. Here is one of the many screens for changing Mach3 settings:

Notice the "G04 dwell ms" entry in the upper right corner.
The way it works is that depending on whether this item is selected or deselected, the G04 code is interpreted in a different way. There is no need to explain the difference between 3 seconds and 3 milliseconds, and the g-code author may have no idea how his code will be executed.
Let's ignore the sobbing of the operator when his disk goes bad and he has to recreate all the windows and buttons, because that would be offtopic.
The utility we are talking about here is implemented in Mach3. AI writes about it this way:Basically everything is true.
Let's not do the same in LinuxCNC.
The definition of g-code is that it is a description of the tool path and let's stick to it.
The same g-code should be executed in the same way on different machines, and not on each machine differently because the operator changed something in settings...

I think the A 0.000 should align right with the numbers above Z-10,000, where the last two zeros are on top of each other, maybe the dtgs could get a slightly less bright red to distinguish them more visibly.

Not sure why A and B needs the smaller text size, but looks ok.

You are removing information though, the Abs might deserve a switch, maybe on click/tap? maybe with some kind of hint, clicking on dtg changes it to abs?

Food for thoughts, not implementation requests

Currently there is much (unused) space between the axis letter and the value:

 

I thought the space could be used more effectively, so I moved one of the tiny sized values to the right and display the labels only at the top. 

 

And I would display the current coordinate system (G5x) fixed at this position and only toggle the display of the right part.

For more than 4 axes I would only display the main value:
 


What do you think about that new design?

 

Yes, I will try to make the least assumptions as possible, you could be working from Z0 center, or not, you could be working on a lathe or a mill, the spindle could be spinning or the table, you might want the feed to match the tip the side or half way trough the shaft of a tool, I think we need some flexibility, but I'd also compare with what other controllers do, and what a CAM or someone hand writing a gcode would expect...

Just thinking about this a bit...

I wonder if a new non-modal gcode could be created that didn't use any INI settings, and simple calculated the appropriate angular feedrate based on the Z0 being at the center of rotation.

In my CAM I have to set A-axis CoR to Z0 for it to work properly, even for simple indexing work.  I wonder if other users are 'used to' programming a rotary axis - at least a 4th axis - with CoR as Z0?

I also wonder if this is going to be more complicated... what if the tool is not just cutting on the rotational axis centerline?  Will the new Gcode/Mcode change (or work with) the trajectory planner to determine the 'real' radius based on rotational axis offset, plus tool diameter?

Sounds like it might get interesting.

Problem is if "stupidly slow" was a behavior anyone relied upon, or already based something on, tuxcnc has a point there, there could be subs out there that fixed this issue in gcode, and we might not what to change their behavior with a new default, is just something we have to account for, we have enough users where these seemingly rare occurrences might bite quite a few ppl...
A new INI to force a sensible default, and leaving old configs unchanged seems the right balance.

---

And replying "G93 works for me" is totally fine, this was more of a census to see how many users actually would use the feature, and who already had it covered, one doesn't detract from the other, but give me a rough idea of who looked at it, and who I can ping for testing once it's built

These are mathematical heresies

Sure, but as I noted, sometimes I forget to use G93 and happen to include an A move in something innocuous, and it would be nice if the resulting motion was at least within an order of magnitude of correct instead of the default of stupidly slow.
Also, my third option gave the machine the math it needed to calculate the correct speeds.