I just got my aluminum AR3 up and running yesterday. I was/am getting tons of interference on my encoders and limit switches. This is manifesting in frequent erroneous reported limit/home switch closures and the motor position readings moving while the robot is at rest. I switched all the motors to open loop on the calibration page, and moved some of my cables/wires around. I noticed that the instructions did not call for grounding the shielding cable on the encoders and that the home switches have zero shielding and run parallel to unshielded stepper motor cables.
I invite anyone who has worked through this issue to offer some simple advice/best practices that might eventually work there way into the extensive assembly document.