On 2010-11-10 18.23, Vinzenz Bargsten wrote: > Hi, > > can someone provide (more) information on how to run a RTnet > in combination with in this case one non-Linux/non-RTnet, i.e. windows > machines? > > The windows machine (robot controller), which runs some proprietary real-time > software, > sends a UDP packet with XML strings every 12ms to the Linux machine. > The Linux machine receives and processes the data (<1ms) and has to answer in > less than 12 ms. > > At the moment,the setup on the Linux machine is: > kernel 2.6.32-7 x86_64 with xenomai 2.5.1, RTL8139 NIC > The data processing is done in/via OROCOS in a real time task. > There is no other machine on this network. > > However, the problem is that the real time requirement is not met, > i.e. the answer from the linux machine sometimes takes more than 12ms. > Using wireshark we found out, that normally the answer is sent after (packet > receive time) + ~0.5ms, > but after some time (minute(s)), it takes >40ms and several/the missing > packets > are sent at once. Could it be that you are running a SMP machine? Then this might be of interest:
https://mail.gna.org/public/xenomai-core/2010-11/msg00053.html later kernel, but the bug might exist in earlier versions (Jan can you comment on this)? > > This is a big problem, as the packets, which are sent from the Linux machine > contain position data, > which should be commanded to a robot. > If the packets are delayed, the robot will stop/hold its position for this > time, > which results in an non-smooth/impulsive movement, making the measurement > useless. > > So, what is the correct procedure to make the network interface working in > real > time mode with a non-TDMA capable remote station? > Is it possible with RTnet, does it make sense? > As the communication is already working with a definite rhythm, I think the > TDMA > functionality is not necessarily required. Is this true? > > > I thought about the steps mentioned in this thread or changing the rtnet > start > script: > http://www.mail-archive.com/rtnet-users@lists.sourceforge.net/msg02187.html > > However I am not sure which commands are required and which are not, to set > up > the interface. > The basic/standard installation of RTnet worked so far. > > Thanks and kind regards > Vinzenz Bargsten > Regards Anders -- Anders Blomdell Email: anders.blomd...@control.lth.se Department of Automatic Control Lund University Phone: +46 46 222 4625 P.O. Box 118 Fax: +46 46 138118 SE-221 00 Lund, Sweden ------------------------------------------------------------------------------ The Next 800 Companies to Lead America's Growth: New Video Whitepaper David G. Thomson, author of the best-selling book "Blueprint to a Billion" shares his insights and actions to help propel your business during the next growth cycle. Listen Now! http://p.sf.net/sfu/SAP-dev2dev _______________________________________________ RTnet-users mailing list RTnet-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rtnet-users
