Hi, I've just finished my mill cnc drive using Gecko's. I kept all the low power 0v lines going direct to the low power board and the high power 0v lines to their respective power supply caps. I then ran a single line from each power supply 0v to a single bolt on the chassis, this is then connected to earth. I've had no problems with any interference as yet.
Dont know about the differential board though. I hope you can get help on that.
Regards
John |