Install linuxcnc raspberry

RaspberryPi

Raspberry Pi running linuxcnc

14Sep2018 news RPi3BPreemptRT prev version preserved for author

Okay brief revision and I hope a better overview of current state.

Raspberry Pi will run linuxcnc but there are many problems still to overcome, I think maybe raspberry pi could be better in some respects than the beagleboneblack, but still too early to tell for certain.

linuxcnc will compile and run and drive motors simply from the base raspbian distro, but does not offer realtime unless you spend a large amount of time compiling a realtime kernel.

To compile linuxcnc from the standard raspbian distro use the following commands:

Does it need a name?

I thought maybe linuxcnc PiCNiC?, or linuxcnc Raspberry PiCNiC? as a fork although probably best not to fork as I doubt there is any need, but maybe a good name for interface boards etc.

Real Time

First realtime, there is a possibilty hard real time kernel may not be absolutely necessary if I/O is moved off to external hardware and handled properly with large prebuffering. Even the realtime kernels do not give great performance and this means a fast basethread and software step generation is not really possible.

When I define kernel as ‘works’ means that it compiles and runs linuxcnc and will drive I/O

  • Xenomai works
  • RT_PREEMPT works
  • RTAI does not work, probably never will
  • Standard linux kernel with preempt and posix threads works, but maynot guarantee timing schedules

Interfacing

Due to the poor realtime performance I/O requires special consideration as software stepgen is probably not possible unless improvements can be made in the realtime kernels.

possible ways of constant step pulses and reducing load on processor

  • GPIO direct by processor (limited by the base thread time)
  • Off board I/O hardware based on one to the serial buses(which have independant hardware buffers, but the buffering does not guarantee timing so intelligent mcu must be used )
  • Off board I/O hardware based on GPIO paralell writing bulk blocks to the I/O hardware (probably much faster than serial but needs more cpu power)
  • GPIO switched by DMA (this is complicated by the problem of how to control step timing)
  • methods not yet considered??

The best options so far are a pic32 based SPI interface board called ‘picnic’ or using the DMA based gpio control, I do prefer the idea of the picnic as it probably protects the rpi and does voltage level conversions handles other IO types like pwm and ADC and other problems can be handled better, but unfortunatly maybe a large extra cost.


  • Forum thread of discussions http://linuxcnc.org/index.php/english/forum/18-computer/20514-emc2-running-on-raspberry-pi
  • Michael’s early latency test results http://linuxcnc.mah.priv.at/rpi/rpi-rtperf.html
  • kinsa pic32 base external I/O interface board http://code.google.com/p/picnc/
  • RT_PREEMPT realtime kernel SD card image of linuxcnc with DMA based fast GPIO interface (I like to think this is currently the best way to demo linuxcnc on the rpi, but it is really only a test version for experts only to give feedback) http://soundproofingforum.co.uk/rpi_linuxcnc/raspberrypilinuxcnc.htm

Kernels

  • RT_PREEMPT (currently has possible problems with mmc card, but seems to work mostly)
  • raspbian default kernel. only for linuxcnc simulator build (simulator will drive motors but scheduling is not real time guaranteed).
  • RaspbianXenomaiBuild

Touchscreen

Sorry but I have erased most of this section as I have heard that rpi touchscreen will be developed by the rpi foundation for release within 6 months and will be far cheaper than any alternative, as I doubt linuxcnc will be suitable for real world use before the touchscreen is released it seems pointless considering anything other than the official touchscreen.

Источник

RaspbianXenomaiBuild

This wiki page is inaccurate and outdated. Instead of modifying this wiki page, create github pull requests for the official documentation on building LinuxCNC. You can read the current version of the compilation instructions here: http://linuxcnc.org/docs/master/html/code/building-linuxcnc.html

LinuxCNC master branch now includes support for Xenomai realtime, configure —with-realtime=uspace

Creating a minimal Raspbian based LinuxCNC image for Raspberry Pi


1. Note


2. Prerequisites


3. Build Xenomai kernel


3.1. Install cross compiler


  • Download and untar the crosscompiler from https://github.com/raspberrypi/tools/archive/master.tar.gz

3.2. Download source files and patches


  • Download kernel

  • Download firmware

  • Download Xenomai

  • Download patches

3.3. Apply patches


  • Apply 3.2.27 patch

  • Apply Xenomai 2.6.1 patch

  • Apply Raspberry Pi Xenomai patch

3.4. Compile kernel


  • Create build directory

  • Configure kernel

  • Or download and use a minimal configuration file

  • Compile

  • Install modules

  • Install headers

The linux-rpi-3.2.27/build/dist directory contains the kernel headers and modules while the kernel image is at linux-rpi-3.2.27/build/arch/arm/boot/ .

4. Create minimal Raspbian image


4.1. Install required packages


4.2. Build image using debootstrap


    • add the raspbian mirror used to /etc/apt/sources.list


  • Or on RPI

4.3. Configure Raspbian


  • Edit /etc/hostname

  • Edit /etc/hosts

  • Edit network interface

  • Edit /etc/fstab

  • Create /etc/resolv.conf

  • Chroot

  • Set locale to ignore warnings

  • Install required packages

  • Cleanup Apt cache

  • Create xenomai group

  • Create new user

  • Configure udev rules

  • Exit chroot

  • Install Xenomai kernel modules and headers

5. Build LinuxCNC


6. Create SD card image

  • Format partitions

  • Mount partitions

  • Populate ROOT

  • Populate BOOT

  • Unmount partitions

  • Compress image

  • Install image

7. Post-install


  • Configure locale

  • Configure timezone

8. Testing


  • SSH to RPi

  • Xenomai latency test

  • LinuxCNC latency test

9. Pre-built image

This pre-built image does not have libgl1-mesa-swx11 installed (this package is needed by Axis)

  • Download

Источник

Getting LinuxCNC

This section describes the recommended way to download and make a fresh install of LinuxCNC. There are also Alternate Install Methods for the adventurous. If you have an existing install that you want to upgrade, go to the Updating LinuxCNC section instead.

LinuxCNC requires a special kernel with real-time extensions. There are three possibilities here: preempt-rt, RTAI or Xenomai. In addition there are two versions of LinuxCNC which work with these kernels. See the table below for details.

Fresh installs of LinuxCNC are most easily created using the Live/Install Image. This is a hybrid ISO filesystem image that can be written to a USB storage device or a DVD and used to boot a computer. At boot time you will be given a choice of booting the «Live» system (to run LinuxCNC without making any permanent changes to your computer) or booting the Installer (to install LinuxCNC and its operating system onto your computer’s hard drive).

The outline of the process looks like this:

Download the Live/Install Image.

Write the image to a USB storage device or DVD.

Boot the Live system to test out LinuxCNC.

Boot the Installer to install LinuxCNC.

1. Download the image

This section describes some methods for downloading the Live/Install Image.

1.1. Normal Download

For x86 PCs Download the Live/Install CD by clicking here:

For the Raspberry Pi a complete SD card image is available here:

This can be installed using the normal Pi install process including with the Raspberry Pi Imager app.

This SD image is reported not to work with the Raspberry Pi4 8GB model. Note also that this version of the SD image limits available memory to 3GB as this is necessary to persuade it to run with both WiFi and USB working on some versions of the Pi. You can experiment with removing this limit by editing the config-rt.txt file in the boot directory. If you can’t boot after the change then the file can be edited back by mounting the SD card in a a different computer (maybe even a Pi with a USB card reader)

1.2. Download using zsync

zsync is a download application that efficiently resumes interrupted downloads and efficiently transfers large files with small modifications (if you have an older local copy). Use zsync if you have trouble downloading the image using the Normal Download method.

Install zsync using Synaptic or, by running the following in a terminal

Then run this command to download the iso to your computer

Источник

Getting LinuxCNC

This section describes the recommended way to download and make a fresh install of LinuxCNC. There are also Alternate Install Methods for the adventurous. If you have an existing install that you want to upgrade, go to the Updating LinuxCNC section instead.

LinuxCNC requires a special kernel with real-time extensions. There are three possibilities here: preempt-rt, RTAI or Xenomai. In addition there are two versions of LinuxCNC which work with these kernels. See the table below for details.

Fresh installs of LinuxCNC are most easily created using the Live/Install Image. This is a hybrid ISO filesystem image that can be written to a USB storage device or a DVD and used to boot a computer. At boot time you will be given a choice of booting the «Live» system (to run LinuxCNC without making any permanent changes to your computer) or booting the Installer (to install LinuxCNC and its operating system onto your computer’s hard drive).

The outline of the process looks like this:

Download the Live/Install Image.

Write the image to a USB storage device or DVD.

Boot the Live system to test out LinuxCNC.

Boot the Installer to install LinuxCNC.

1. Download the image

This section describes some methods for downloading the Live/Install Image.

1.1. Normal Download

For x86 PCs Download the Live/Install CD by clicking here:

For the Raspberry Pi a complete SD card image is available here:

This can be installed using the normal Pi install process including with the Raspberry Pi Imager app.

This SD image is reported not to work with the Raspberry Pi4 8GB model. Note also that this version of the SD image limits available memory to 3GB as this is necessary to persuade it to run with both WiFi and USB working on some versions of the Pi. You can experiment with removing this limit by editing the config-rt.txt file in the boot directory. If you can’t boot after the change then the file can be edited back by mounting the SD card in a a different computer (maybe even a Pi with a USB card reader).

1.2. Download using zsync

zsync is a download application that efficiently resumes interrupted downloads and efficiently transfers large files with small modifications (if you have an older local copy). Use zsync if you have trouble downloading the image using the Normal Download method.

Install zsync using Synaptic or, by running the following in a terminal

Then run this command to download the iso to your computer

Источник

Getting LinuxCNC

This section describes the recommended way to download and make a fresh install of LinuxCNC. There are also Alternate Install Methods for the adventurous. If you have an existing install that you want to upgrade, go to the Updating LinuxCNC section instead.

LinuxCNC requires a special kernel with real-time extensions. There are three possibilities here: preempt-rt, RTAI or Xenomai. In addition there are two versions of LinuxCNC which work with these kernels. See the table below for details.

Fresh installs of LinuxCNC are most easily created using the Live/Install Image. This is a hybrid ISO filesystem image that can be written to a USB storage device or a DVD and used to boot a computer. At boot time you will be given a choice of booting the «Live» system (to run LinuxCNC without making any permanent changes to your computer) or booting the Installer (to install LinuxCNC and its operating system onto your computer’s hard drive).

The outline of the process looks like this:

Download the Live/Install Image.

Write the image to a USB storage device or DVD.

Boot the Live system to test out LinuxCNC.

Boot the Installer to install LinuxCNC.

1. Download the image

This section describes some methods for downloading the Live/Install Image.

1.1. Normal Download

For x86 PCs Download the Live/Install CD by clicking here:

For the Raspberry Pi a complete SD card image is available here:

This can be installed using the normal Pi install process including with the Raspberry Pi Imager app.

This SD image is reported not to work with the Raspberry Pi4 8GB model. Note also that this version of the SD image limits available memory to 3GB as this is necessary to persuade it to run with both WiFi and USB working on some versions of the Pi. You can experiment with removing this limit by editing the config-rt.txt file in the boot directory. If you can’t boot after the change then the file can be edited back by mounting the SD card in a a different computer (maybe even a Pi with a USB card reader).

1.2. Download using zsync

zsync is a download application that efficiently resumes interrupted downloads and efficiently transfers large files with small modifications (if you have an older local copy). Use zsync if you have trouble downloading the image using the Normal Download method.

Install zsync using Synaptic or, by running the following in a terminal

Then run this command to download the iso to your computer

Источник

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