Emi interference

Having some issues with the X2 system and my hypertherm power max 1000g3 all updates applied and re applied after resets calibration is good but when I move the arc droid while my plasma cutter is on the x axis readout just goes nuts reading plus or minus 300 inches this even happens without the ground attached as well as a note the plasma cutter is located about 15 feet from the arc droid while this is taking place and the arc droid runs fine other wise I can even run X2 programs as long as I power off the plasma cutter before moving the arc droid
Is an earth ground the correct solution and if so how to properly set it up?