Non-linear error compensation; PCD hole positioning on circumference; 200 points auxiliary zero position function; High-capacity ROM disc for storage; Real time coortransmission with RS232; File transmission function through USB; Four coordinate system are adopted in thsi system, namely, machine coordinate system, absolute coordinate system,relative coordinate system and 200 user coordinate system; Metric/British units switching display;Software diagnosis function; AB function to search for the reference point of encoder; Power off momory function.