Manual on page 3 http://linuxcnc.org/docs/devel/pdf/LinuxCNC_Developer.pdf
NML should work over TCP/IP networks including Ethernet but think it is currently out of order and only work using shared memory buffers. Try to get it started using ordinary TCP/IP over ordinary Ethernet network a few years ago, might be axis which is the problem.
Ethernet is not well suited for real time control, it is however possible in a controlled environment or if some missed dead lines may be accepted. There is a difference between video and machine control, amount of data is relatively small in machine control but with control loop over network it have to be sent very often. Interestingly old ATM for telephone network send many small messages, read something about 48 bytes.
Main problem with Ethernet is then connected to an ordinary network. Other messages may arrive at any time and if they are sent first real time communication is delayed. Have not yet figured how to tell Linux to not send other communication then used as a real time controller though probably not very hard, then listening with Wireshark there are coming out arp request and other request on the Ethernet port.
Nicklas Karlsson Den 2022-04-16 kl. 01:23, skrev Torsten Curdt via Emc-developers:
Hey there, I was wondering the following - and mainly really to understand how LinuxCNC works. Since I couldn't get a proper answer in the user chat I thought I would try here. IIUC the GCODE interpreter runs in the non-realtime part. It sends the step instructions to a card to execute the steps. This is obvious when using a LPT port, but how does this work via Ethernet? Are the steps compressed into instructions and then applied on the Mesa cards? Poking around it seems like there are motion commands and status commands? So it probably sends "go there" and "where are you" and the card generates the steps required and reports back. Does that sound right? Is there a definition of the protocol to look at? I assume the code of what gets pushed to the Mesa's must be somewhere, too. And now I hope I don't get lynched for asking: How is that ethernet protocol different from the Mach3 ethernet protocol? Are there significant differences between the protocols that would prohibit LinuxCNC speaking the Mach3 ethernet protocol? Or maybe no one knows or cares? But I was wondering if implementing the protocol could be another alternative to flashing Remora to supported boards. While waiting for Mesa stocks to recover, I am really just curious to understand the technical side of the LinuxCNC vs Mach3 comparison. cheers, Torsten _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
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