Hi Sam,

I ran into the same issue(s) when I attempted to calibrate the robot for the first time. In short, my solution was to reverse the black and red wire on each limit switch - the manual is incorrect or I introduced an extra wiring error.

Here's what I did:

-> After building the robot, manually positioned the robot to be roughly in the "rest" position, programmed the Teensy 3.5 and established communication with the Teensy in the AR3 control software, and with the robot control box fully powered on, I navigate to the calibration tab.

-> In the calibration tab, I selected the "Calibrate J1 Only" button.

At this point, the machine rotates clockwise, stops, rotates counterclockwise slightly, then clockwise again a little before completely stopping with an error about either the limit was tripped or the joint is out of calibration. From my understanding, the machine should rotate towards the limit switch making contact, reverse direction to release the switch, then re-establish contact with the limit switch before stopping with calibration achieved for that joint / motor / axis.

The issue repeats on all joints / motors / axis. With a multimeter, I read approximately -5V when pressed (ground reference is the ground pin to the GX16-2 connector) and 0V when not pressed.

The solution for myself was to reverse the black and red wires for all limit switches so that I read approximately 0V (pressed) and -5V (not pressed). From here, I can calibrate each axis individually as before, with success.