I was lucky enough to attend an Ethercat working group seminar today in Brisbane, Australia where German based Martin Rostan, Executive Director from the EtherCAT Technology Group (ETG) was the main presenter.
It was all very interesting and the detailed low level description of ethercat packets and alternatives based on TCP makes Ethercat streets in front of other alternatives because of the sheer efficiency of the protocol. This let me understand the issues causing the error finishing read error being experienced with hm2eth connected devices (ie mesa ethernet cards) in later kernels (5.10 and above). I was also able to speak with Martin about the licensing issue preventing us from including the Linuxcnc ethercat driver in our distribution and have a greater understanding of the problem. Their license requires users of an ethercat master (in this case the iGh Etherlab master we use) to become members of the ETG (which is free). Anybody selling machines would need to adhere to this. So technically, we can't put that condition on to our terms because the existing GPL licence from Linuxcnc propagates to the ethercat driver. He did go on to say that they would never take action against somebody promoting use of ethercat masters. So back to the error finishing read problem (that can't be solved by wide scale adoption of ethercat), I recently purchased an Odroid N2+ Arm based PC which arrived today. I was hoping the different platform may improve network latency. I have been able to compile an Armbian bookworm image which booted OK. A user on the Armbian forum is willing to help me with building a PREEMPT_RT image following this prerequisite first step. but his main interest is in Xenomai 4 and he is keen to help me subsequently build Xenomai for the N2+. Xenomai seems to have a significant advantage over PREEMPT_RT re latency. Given we already support Xenomai 3, I am hoping it will be a fairly simple matter to support xenomai 4 and build a test for network latency to look at differences between xenomai and preempt_rt. So I am sure progress will be slow, but I am hopeful we will come up with a solution to error finishing read! I hope some of you are interested in this ChatGPT free update! Rod Webster VMN® www.vmn.com.au Ph: 1300 896 832 Mob: +61 435 765 611 _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
