We created universal PCB that can be used as an Arduino shield or as a stand-alone CNC stepper motor controller. You can read more about it in one of our previous blog posts.
During testing we attached one shield to Arduino UNO and connect the other one to our precise XY translation table. Two CNC shields communicate with each other via audio Toslink cables.
Since our system enables precise translation table movement control via optical cables we do not need to worry about the EM interferences.
The CNC shield has been fully tested and meets the expectations.