comparing to Grbl, or FluidNC

I'm interested in hearing opinions/thoughts from folks that have use both LinuxCNC, and one of the microcontroller firmware based systems, like Grbl, or FluidNC.  I have long (though perhaps not "deep") experience with LinuxCNC, and I've done some reading a couple of times about the "newcomer" systems, but I've never used one.

I assume that, given a g-code file, any of them will (basically) get the job done.   What I'm interested in hearing about is the things that surprised you, in switching from one to the other.  What was better?  harder?  easier?  worse?  What did you miss?  What made your milling life better?  I know, I know -- changing mill s/w probably doesn't involve life-changing epiphanies.  But I think you understand what I'm wondering about.

This question is triggered mostly by curiosity, and also because I've been window shopping for a new mill lately, and I'm wondering how much I should care about the controller and software that come with it.  It's likely that I'll replace whatever they provide, with my RPi and Mesa card,  but...  maybe not, or, maybe not right away.  I guess I'm wondering what the "dark side" is like.

paul

Well, they're "hobby only", but also "small workshop". I think those systems are used in an awful lot of places, because they're so much simpler to set up.

If I end up with a system that comes with grbl, I'll certainly be interested in trying it. Hope someone else can chime in as well.

paul

Regarding capabilities, FluidNC isn't able to read real-time feedback like encoder input. As I understand it, I must add.
That gives limitations to the use of analog servos (step/dir without feedback to controller is fine), THC but I've got mixed info there.
Stepper motors, R/C servos can be used.
I think it can be a good fit for a 3-axis portal milling machine like a 6040.
Linuxcnc can do "everything", sometime that's not needed especially for uncomplicated machines like the 6040.
 

I retrofitted my first engraver with GRBL; took an Arduino nano, read the manual for 3 hours, connected everything in 2 more hours and had a working system that I used till my spindle controller card burned while milling a pcb... I then retrofitted a small desktop mill and went this time for GrblESP32, which became FluidNC later. Again, the set up was quick, efficient and functional.

I started to read about LinuxCNC when I was trying to use TMC5160 stepper with their internal motion controller rather than with step/dir signal. For me this could be the first big difference; if you look for a G-Code interpreter to generate up to 6 axis step/dir signal at a fairly high frequency and need the standard Start/Stop/Pause inputs, then go for Grbl-like system. If you need more complex interaction with hardware, then LinuxCNC is the answer.

The second big difference is probably the difficulty; maybe not the best example, but after several months I still don't have a working system. But to be fair, it has a lot to do with my poor coding skills, and the fact that my mill is currently working well under FluidNC. Anyway, even for a standard project, you will have to find a reliable step generator (PC-based or external), find the correct configuration, adapt the INI and hal files, choose a GUI. There are many options and that's fantastic, but it takes time to figure everything out. FluidNC works on ESP32 and uses one config file. That's it.

Speaking of figuring things out, this forum is certainly the third big difference; yes, FluidNC has a nice wiki, yes 3D printing Grbl-like systems like Klipper, Marlin, etc have also a lot of users and forums. But this forum is a real gold mine and there are so many different information about so many different subject that you can spend hours here without thinking about your mill. Congratulations guys!

The fourth and for now last difference I'll mention is the GUI; as said before, Grbl-like systems are G-Code interpreters and they do not offer any user interface. So one option is to use none and just put your G-Code on a SD card and start it with a button or a small touch screen, or to connect an external PC that will host the GUI. There are different existing software and I don't know them all; I use bCNC and tried UGS. They are very fine for simple setups, to home machine, use camera for alignment, Z and tool probe, etc.

In my current project, I try to use LinuxCNC on a Radxa Zero 3E as a headless 6-axis motion controller. For this, it would be fantastic to have a module similar to linuxcncrsh but "speaking" Grbl standard; I could use any of those existing G-Code sender with my LinuxCNC board. On the other hand, the Remora component use external micro controller to generate steps/dir signals, but in theory, a Grbl component could completely replace the EMCMot+Stepgen components in LinuxCNC for stepper motors signal generation.

Thank you! Your's was exactly the voice of experience I was hoping to hear from.

I love/hate LinuxCNC. On the one hand, I spent hours last night trying to figure out how to get my USB gamepad "wand", which worked fine under 2.7.4, to work reliably under 2.9. On the other hand, it's likely that Grbl/FluidNC wouldn't support the gamepad at all.

I've wondered, too, about whether the Grbl comm protocol could be implemented on the front of LinuxCNC. I know the folks driving industrial mills would be horrified, but it might be a good solution in some cases.

Again, thanks for the feedback.

I don't know where this idea comes from that you need any coding skills to setup Linuxcnc. This is one of the biggest lies attributed to Linuxcnc (Linux in general), it's bullshyte. You don't need to be a coder, even to type instructions at a terminal, no one ever said you need to be a coder to use MSDOS. That was the point of a OS to enable the system to be used by "non computer people" as well as a lot of abstraction & a million other things.

Setting up Linuxcnc for a basic 3 axis mill take no time at all using the Linuxcnc supplied config tools. Whether it's a parallel port or 7i92 based system. The biggest issue I see users have is not paying attention to the errors reported in the error report, things like pin xx doesn't exist, usually it's a typo. Or a user expecting a pin to exist that doesn't. Realtime errors are a PC issue, not really a Linuxcnc config issue.

Whether you axis, gmoccapy or your "grbl module" (whic I think will be a performnce hit in a bad way) you will still need to setup a linuxcnc config, the very thing you've been mentioning.

If you want to use grbl use it, but Linuxcnc is a completely different beast, but don't expect any grbl functionality from Linuxcnc.

Mesa, LlinuxcncRIO & Remora all work along a similar concept, step & direction signal generation is off loaded to the external motion control card.

I don't know why you would want to send a gcode file line by line to linuxcnc when it can open and read the file directly.

One thing that is very intriguing, you admit to poor coding skills, yet propose some major replacement of the Linuxcnc internal workings.

In reality all grbl is is a way to send data via a serial port.

pgf wrote:

Thank you! Your's was exactly the voice of experience I was hoping to hear from.

I love/hate LinuxCNC. On the one hand, I spent hours last night trying to figure out how to get my USB gamepad "wand", which worked fine under 2.7.4, to work reliably under 2.9. On the other hand, it's likely that Grbl/FluidNC wouldn't support the gamepad at all.

I've wondered, too, about whether the Grbl comm protocol could be implemented on the front of LinuxCNC. I know the folks driving industrial mills would be horrified, but it might be a good solution in some cases.

Again, thanks for the feedback.

There were major changes to jogging from 2.7.x to 2.8, so any pendant would need work, that's why one should read the docs to see what has changed before upgrading. Once a again, not a Linuxcnc issue as such but a user issue.

Another good perspective. You're clearly a LinuxCNC guru. How much time have you spent using Grbl or FluidNC?

You mention no need for coding skills: I'd say that any time you open up a HAL file, you're coding, designing arbitrarily complex digital "circuits" in a text file. An incredibly powerful feature, but where's the UI? It's a graphical concept, one that should be supported via a schematic capture tool. But there's no easy way to even display a HAL file, let alone construct it.

"Not a Linuxcnc issue, but a user issue."

A little respect, please. There were fundamental changes, and a small attempt at automating the upgrade. I did read the docs, and I did make the manual changes I thought were required, and it did work... most of the time, and then it would stop working. I think maybe I'm trying to jog the jog the joints instead of the axes. Or else maybe that's fine, and the problem lies elsewhere. But either way, I have a debugging problem on my hands, and after a couple of hours, I'm still not done.