I did some digging myself on this one recently. * With RTnet it only has support for limited network interface chipsets, I don't think this will include the one on the RPi since that's basically ethernet via USB internally, also I'm unsure if it's compatible with the latest kernel. * There was a RTUSB at some point but it seems to have the issue of not being updated in forever and probably only works with certain USB chipsets * The CANBus has the downside of being slow (40 Kbit/s to 1 Mbit/sec) * For EtherCAT it looks as if the shields you can buy (the hardware design is not open source) hook up to the SPI port on the arduino / rpi boards. Slave boards / chipsets seem to be expensive due to licencing and you may have issues writing your own linux drivers for them.
One option I'm thinking of investigating myself is the use of SPI hooked up to a RS485 transceiver as some of those can manage 10Mbits/sec or 100MBits/sec. RS485 would handle any noise problems (since SPI is mostly designed for interboard communications). But I'm unsure of the status of SPI / realtime combination and what the latency / jitter would look like, also it would probably require custom drivers and hardware on both ends. Many Thanks Richard On Wednesday, December 20, 2017 at 9:51:57 AM UTC, [email protected] wrote: > > I found many cases that use BeagleBone Black and Raspberry Pi. RTnet may > be good to control the motor via EtherCAT. > But how to achieve real-time using CAN bus. Or is it just not matters? > -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.
