Advanced Search

Is there any possibility that this is configured as a WRAPPED_ROTARY?

linuxcnc.org/docs/html/config/ini-config...:ini:sec:axis-letter

wiki.linuxcnc.org/cgi-bin/wiki.pl?WrappedRotaryAxes

This isn't elegant, but if your python file imports "hal" then you can create a HAL pin, put the value on that, and then read that value in your G-code.
The most reliable way to do this is to "net" it to one of the G-code analogue inputs and read it with M66. But you can also use the #<hal[mymodule.pinname]> format in the G-code. Just be aware that the latter method will generally get the value that was on the pin when the G-code program starts and won't see any live updates.

linuxcnc.org/docs/html/gcode/overview.html#gcode:ini-hal-params

It's possible that the noise is due to the servos getting a bad rotor "home"
This only applies to brushless motors, but the drives need to know where the rotor magnets are relative to the motor windings.
If you are using EtherCAT then this is probably all inside the drives, so I am not sure how you could ever be sure if this is the problem. Do you know how the drives perform this step? (If they use absolute encoders or hall sensors then this is unlikely to be the problem)

I wouldn't expect G71 and friends to accept REPEAT/ENDREPEAT in the profile subroutine. It parses G1,G2,G3 commands into a profile internally then creates a toolpath to cut that profile.
I am not even sure that it can be expected to correctly read #<_x> etc.

Nice work mate

Ok the screenshots are interesting. Unfortunately I haven't had a chance to check as life has got in the way.
To tell the truth when I test the images I use an old 19" 4:3 monitor. Another thing to be aware of is that the images aren't meant to be for a daily driver, the sole purpose is to run Linuxcnc which is what is concentrated on. So yes there will be packages left out that are part of a standard Desktop install.
The kernel was built using the official RPi sources, with the only mod being enabling the RT section in the kernel config. So there is really nothing fancy in that area.
It very well be an issue related to resolution, in config.txt you should be able to adjust the memory allocated to the graphics system, something you'll have to look at the config.txt documentation, 2 things to be aware of, there is no raspi-config utility so the config.txt will need to be hand edited and the location of it is different to the Raspberry OS, the main thread for the images has this info.
If you just want to explore what Linuxcnc has to offer without running a machine or connecting to any hardware there is also the option of running the amd64 version as a live session on a PC or installing in a virtual machine such as VirtualBox. RT capabilities will be non existent but it will run the simulations fine.
Another option would be to install RaspiOS and build Linuxcnc from source, a real time kernel would not be required in your case and use at ad a Run In Place install. How to do this can be found in the docs.

Thanks for the replies. I finally got a chance to check out the suggestions on the RPi400. For testing I made a new fresh image on a new SD card, and the graphical glitches could be reproduced, but it may be just an issue in chromium browser, which is not installed by default. I did not reproduce the issue in Firefox, and though it is painfully slow to load pages, Youtube does play... eventually.

The SD cards used are 64GB Kingston Canvas Select Plus. Nothing fancy, but I doubt it is the issue, since I've used multiple, and other images (default RPi OS, Ubuntu 24.04) don't have the same issue.

For reference, here are some screenshots of the glitches in chromium. Btw, I had to install xfce4-screenshooter to be able to take screenshots, as it is not installed by default in the LinuxCNC rpi image.

The first screenshot shows a horizontal section of the web page with corrupted graphics. The second is chromium's setting page which never displays correctly. The third is a pdf document opened in chromium, with the controls (download, zoom, etc) at the top not showing. The fourth shows the graphical glitches in the Youtube player controls (buttons for play, pause, settings, etc).

They work in Firefox (very slow though, which is why I installed chromium) so perhaps this is not an issue specifically with LinuxCNC's image, though I can't tell. I don't have these issues with chromium on the other RPi OS images, but I have not tried debian 12 directly. I imagine that also precludes hardware issues. The monitor is a 22" Dell at 1680x1050, though I doubt that is too relevant.

Aside from isolcpu, were there other optimizations made which may impact graphical or general performance?
 

You will need a custom mcode that calls an executable script that uses 'halcmd' to set the appropriate hal pins.

Here is an example that does this but for different hal pins so you will need to modify to meet your needs:
forum.linuxcnc.org/21-axis/53531-change-the-axis-limit#307778

Yeah I didn't remember that right. Then I wonder if that's the problem here.