METHOD OF DETERMINING SUB-DIVISIONAL ERROR

摘要

A method of determining the sub-divisional error of an encoder apparatus that is configured to measure the position of relatively moveable parts of an apparatus on which an inspection device for inspecting an artefact is mounted. The method comprises causing the inspection device to obtain measurements which comprises relatively moving said relatively moveable parts of the apparatus, and using the measurements to determine the encoder apparatus' sub-divisional error.