Accuracy is the relative status of something compared to its absolute or perfect value. In motion control this will most often be a position description. A command may be sent to move 4.0”. The accuracy of the system will be defined by how close to the absolute value of 4.0” the system can affect the move. Accuracy may be defined as a one-time incident or the average over a number of cycles or motions. Positioning accuracy will normally be defined in terms of deviation (+/- from theoretical) or limits (acceptable variation from theoretical: ie. 3.8”-4.2” define acceptable limits of variation around a theoretical point of 4.0”)