No the EL6021, modbus is usually RS-485 signalling. Not so different from RS-232 but differential signals.
Edit. The USB to RS-485 is a much better option in this case to avoid the vertical learning curve.
There is not much difference between E6021 and 6001. I usually use these modules on the codesys platform. If I have more time later, I will try to test linuxcnc, but this means it will take a long time. I will test and release a demo as much as possible.
Why not use an Ethercat VFD like the Omron MX2 which is supported in the hal driver. I believe internally its a cia402 device since it's essentially a speed control for a motor just like a servo!
Thank you so much for your hints and ideas!
Yes the optidrive should stay in my setup - at least for the next months. The switch to ethercat, the new servos aso was hard enough to afford. As you mentioned before usb to rs485 is an option, I will go that way until I will be able to spend the next bucks for an ethercat VFD.
