This is also a good reason to use Ethernet (or Ethercat). All Ethernet cables are galvanically isolated by transformers. I think this is a little known fact, Ethernet uses magnetic isolation to prevent ground loops.
This is kind of a big deal in a large system. Some types of signals just cannot go over long distances and the only way to use the types of signals that can travel long-distance is to have some kind of "intelligent" device at the far end. On Sun, Mar 10, 2019 at 3:16 AM Nicklas Karlsson <nicklas.karlsso...@gmail.com> wrote: > > > > -----Original Message----- > > > From: Chris Albertson [mailto:albertson.ch...@gmail.com] > > > > > > > The STM32 has no problem with MHz level bit flipping. Reading or > > > creating is MHz level is not hard. > > > And the Pi3 has to be about the most well understood and documented > > > machines on Earth. they > > > are ultra-common. > > > > > > The pi still is beat by an Intel desktop PC but the Pi has that GPIO > > > header and you can get at signals. The OS causes unpredictable > > > latency so use the STM32 if that matters. > > > > > > As for compute power if the Pi is not enough you offload from the Pi > > > to the bigger box. But for machine tools the Pi is overkill unless > > > you are doing vision. > > > > > And the STM32s are so inexpensive that the STMBL AC Servo drive uses two of > > them. One to handle the actual 3 phase drive output and one to deal with > > the encoders and user interface etc. It's a nice solution where the > > computer side (LinuxCNC) is electrically isolated from the 350V Motor side. > > There are good reason to place Micro controller on rectified negative rail > while other signal need to be electrical isolated. This might be the reason > two micro controllers are used. > > > Nicklas Karlsson > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
