A method for calibrating a controller of a robotic arm in a microelectronics manufacturing apparatus that includes storing a default position for an edge detector, moving a blade on the robotic arm based on the default position of the edge detector such that at least three edge points on the blade pass through and are detected by the edge detector, generating a plurality of arm position measurements from an arm position sensor by measuring a position with the arm position sensor of the robotic arm at each position of the robotic arm at which an edge point of the blade is detected by the edge detector, and determining at least one of an actual position of the edge detector and an offset for measurements of the arm position sensor based on the plurality of arm position measurements.