Location Variables When you are using a robot, the local frame of reference defined by the XYZ components is located at the end of the robot tool flange. (This local reference frame is referred to as the tool coordinate system.) In the figure Yaw, the large Cartesian space represents a world coordinate system. The small Cartesian space represents a local tool coordinate system (which is centered at the motion device tooling flange). Yaw eV+Language User's Guide, v2.x, 18318-000 Rev A Page 105