My sentiments exactly. On 2016-02-04 16:50, Chris Morley wrote: > Seddddddsssdsssssssssdds > > ----- Reply message ----- > From: "Nicklas Karlsson" <[email protected]> > To: "EMC developers" <[email protected]> > Subject: [Emc-developers] Prempt RT on Raspi/ARM (Preemt RT improved) > Date: Wed, Feb 3, 2016 11:28 PM > > > I discovered yesterday Preemt RT have changed so that it handles priorities > for interrupts properly. Or at least as good as possible because there may be > SMI, System Management Interrupts in bios. My reasonable modern quad core > computer have a maximum delay of around 50µs, it is not as good as a micro > controller but good enough for a reliable 1ms thread. > >> We in fact do use hardware to make things better - just as the lowest level >> possible. Build a micro controller that reads encoders and outputs PWM >> and that is a good fit for linuxcnc and they are very good at that. > I have micro controller that read encoders and output PWM and it is in sort > of built for this task. To send encoder output to linuxcnc for position > control loop is a detour and I will modify later to send position directly. > The micro controller I have chosen is available from around $1 in high > quantity although maybe only one motor for this price otherwise it is two. > >> Of course I mostly look from a big machine control side - if you are wanting >> to operate something else I can see wanting to use a tablet or phone and >> in this case the GUI being separate would be very helpful. >> But that still doesn't mean putting the motion controller inside a >> microcontroller. > It would be good to separate GUI. The motion must be put on something running > real time reasonable well but demand is not very high. > >> In all I don't see the motivation for putting the motion controller anywhere >> but were it is - unless coding motion controllers in micro controllers is >> something >> you just like to do. (which certainly is not a bad thing) > If motion controller is put on micro controller there will be nothing else > except communication protocols and this is an advantage compared to a Linux > operating which is rather complex. > > I have written software many times where I used nested interrupts with > priority for scheduling and this is a very simple easy to understand system > if there are only a few tasks. It does not work for large systems but it keep > software simpler for small systems. > > Nicklas Karlsson > > ------------------------------------------------------------------------------ > Site24x7 APM Insight: Get Deep Visibility into Application Performance > APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month > Monitor end-to-end web transactions and take corrective actions now > Troubleshoot faster and improve end-user experience. Signup Now! > http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > ------------------------------------------------------------------------------ > Site24x7 APM Insight: Get Deep Visibility into Application Performance > APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month > Monitor end-to-end web transactions and take corrective actions now > Troubleshoot faster and improve end-user experience. Signup Now! > http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers
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