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2023-06-06 - 04:49

Dates and Events:

OSADL Articles:

2023-03-01 12:00

Embedded Linux distributions

Results of the online "wish list"

2022-01-13 12:00

Phase #3 of OSADL project on OPC UA PubSub over TSN successfully completed

Another important milestone on the way to interoperable Open Source real-time Ethernet has been reached

2021-02-09 12:00

Open Source OPC UA PubSub over TSN project phase #3 launched

Letter of Intent with call for participation is now available

2016-11-12 12:00

Raspberry Pi and real-time Linux

Let's have a look at the OSADL QA Farm data

Real Time Linux Workshops

1999 - 2000 - 2001 - 2002 - 2003 - 2004 - 2005 - 2006 - 2007 - 2008 - 2009 - 2010 - 2011 - 2012 - 2013 - 2014 - 2015

15th Real Time Linux Workshop, October 28 to 31, 2013 at the Dipartimento Tecnologie Innovative, Scuola Universitaria Professionale della Svizzera Italiana in Lugano-Manno, Switzerland

Announcement - Call for participation (ASCII)Hotels - Directions - AgendaPaper Abstracts - Presentations - Registration - Abstract Submission - Sponsors - Gallery

The LinuxCNC Machine Control Portable Realtime API

Michael Haberler, The LinuxCNC Project
Alexander Rössler, The Vienna Reprap Group

LinuxCNC, a package to control machine tools such as milling machines and lathes, until recently was limited to RTAI and hence x86 platforms. OS support has been abstracted to provide package-level binary compatibility over RTAI, Xenomai and RT-PREEMPT kernels, supporting RTAI and Xenomai kernel threads, and Xenomai, RT-PREEMPT, and Posix userland threads. LinuxCNC ARM7 builds are active use in the BeagleBone, Raspberry and Reprap communities.

We present an overview the "electronic circuit"-style HAL realtime component architecture, and the requirements for, and implementation experience with the portable RTAPI layer which HAL rests on: component handling, threading, unified shared memory, exception and log handling.

We discuss the impact of measured latency figures at the RTAPI layer in machine control terms: commanded path noise causing position hunting and PID loop excitation, and tool stress caused by angular noise in electronically geared motion, as well as potential software countermeasures.

A demonstration of LinuxCNC on a BeagleBone, running a MendelMax 3D printer with high-speed steppers driven by the AM3359 programmable realtime unit (PRU) will be given in the break.