thanks..
bkt
2017-06-12 0:47 GMT+02:00 Nicklas Karlsson <***@gmail.com>:
> I read and it mostly seems to be about security. Realtime scheduling make
> sense for every task which is periodic or may be treated as a periodic
> task. A really good example is a serial receive buffer since data will be
> lost if not handled periodically.
>
> GUI I usually treat as periodic task with a dead time of about 20-50
> milliseconds even though it seldoms happens. Video I guess is about 30-50
> milliseconds. Servo loop is around 1 milliseconds and even though little
> computational power is required ordinary computer seems to have problem
> with this.
>
> They mention something about support for a real time operating system and
> for linuxcnc the kernel RT patch is used or RTAI. On a micro controller I
> most often use an interrupt with suitable priority, software is most often
> simple with only a few well known interrupts so most often it works really
> well.
>
>
> The most useful scheduling schemes are Earliest Dead Line first
> https://en.wikipedia.org/wiki/Earliest_deadline_first_scheduling and for
> static priority rate monotonic which may be implemented with nested
> interrupts with priority https://sv.wikipedia.org/wiki/
> Rate-monoton_schemal%C3%A4ggning
>
> Dead line should be equal to periodic which most often is possible. For
> video with a dubble buffer, for serial receive buffer interrupt is
> triggered then buffer is half full, ... It is commmon to talk about jitter
> which make som sense but for properly implented EDF or rate monotonic
> scheduling jitter within period make no difference.
>
>
> Here http://linuxcnc.org/docs/2.6/html/code/Code_Notes.html at "4.
> Architecture overview" is probably what you need to understand how the
> different parts of linuxcnc is put together. The real time part I want to
> put on simple computer and the GUI on an ordinary computer since they are
> readily available cheap. There are two advantages: I want to keep real time
> communication local and remove real time demand from ordinary computer.
>
>
> Regards Nicklas Karlsson
>
>
>
> On Sun, 11 Jun 2017 23:19:27 +0200
> theman whosoldtheworld <***@gmail.com> wrote:
>
> > see these:
> > https://blog.qt.io/blog/2017/05/17/integrity-rtos-support-qt-5-9-lts/
> ...
> > As you said, me too I try is little bit hard use qt c++ program instead
> > Lcnc c/c++ for driving servos machines .... but it promise rtos realtime
> so
> > sometings is for certain possible ... any how the goal for new qt5.9 rt
> is
> > automotive industries ... not robotics or chips machines ...the common
> > denominator is sending realtime command signals and receiving them, a
> > little logical work to make the signal available and allow the operator
> to
> > see or send these signals. Taking the sums I think is the first test to
> > pave the way for the qt to the future automatic driving machines.
> >
> > my intention is use qt5.9 to interface a gui using a modern opensource
> > industrial bus, with other electronics devices and some pc with Lcnc
> > without gui.I'm not going to use the industrial buses to drive the servo
> > ... I find it safer to use the command and safety buses (even in the
> servo)
> > and use traditional piloting for the positioning and the feedbak ... so
> two
> > different line to the servo on two totally different channels, analogue
> for
> > driving, digital for safety and functional. It's like having two dogs who
> > are guarding one against each other.
> >
> > The project would be: to create an rt component that starts as if it
> were a
> > gui at opening lcnc, the component starts a server connection of some
> > industrial bus and waits for queries from slaves or slaves, as for
> example
> > some commands / requests may arrive From a plc of security; Create a gui
> in
> > qt on remote pc having its main thread, secondary ones of service and
> then
> > one or more thread rt for communication to pc lcnc via industrial bus rt
> or
> > other devices (eg plc security).
> >
> > I've already relayed this thing with modbus as a test ... but modbus,
> even
> > turning very fast with new technologies, even over 115000, always sends
> 16
> > bits at a time ... for good remote control Of Lcnc serve at least 48 bits
> > for the on / off commands + others to have floats .... so a fast and
> large
> > bus is what you need ... believe that's why Sebastian has used QUIC.
> >
> > I'm happy to chat with you about this.
> >
> > bkt
> >
> >
> > 2017-06-11 17:21 GMT+02:00 Nicklas Karlsson <
> ***@gmail.com>:
> >
> > > On Sat, 10 Jun 2017 22:48:47 +0200
> > > theman whosoldtheworld <***@gmail.com> wrote:
> > >
> > > > ... thanks for your advice ... but there are 3-4 solution for these
> > > things
> > > > ....
> > > > But at present I am more concerned with understanding the use of
> various
> > > > Lcnc files than any other.
> > >
> > > The lcnc files are a little bit hard to understand. The *.hal files are
> > > almost like netlists used for schematics. It make a lot more sense to
> > > visualize the configuration in schematic.
> > >
> > > There are some old almost working example with geda gschem, whenever I
> > > have a few I will try to get the script to work. I also heard something
> > > about rockhopper, it is also vizualized graphically although this was
> some
> > > kind of web based interface, html have limitations then it come to user
> > > interfaces and usually have a second or so delay whenever something is
> > > pressed. Graphical representation with gschem should be simple, script
> is
> > > currently in python while most other output from gschem via gnetlist
> is in
> > > scheme language.
> > >
> > >
> > > I am fully with you then it come to split application in non real time
> GUI
> > > and real time. And at least partly with you then it come C++ and do not
> > > like python programming language but use whatever is available or have
> been
> > > used before.
> > >
> > >
> > > Then it come to GUI I like the glade interface designer and automatic
> > > connection of callback functions. Automatic connection of callback
> > > functions are available in C but not C++ and for python I do not know.
> > >
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