Length and angle measurement system for machining tool or robot - uses ruler whose measurement divisions comprise absolute coded elements and incremental elements and scanner unit with read-off device

摘要

The system has the scanner unit (6) adjustable in the measurement direction relatively to the ruler and has read-off devices (8, 14-17) for prodn. of measurement signals from reading the division elements. An evaluation unit (9) determines absolutely the momentary position of the scanner unit (6) to the ruler (1) from the measurement signals of the read-off devices. The coded measurement division elements comprise different code words (4) in serial codification which follow one after the other in the measurement direction. The read-off device (8) is a multi-line detector, partic. formed by a CCD chip or a diode line array, which in each relative position of the scanner unit to the ruler records completely at least one code word. The read-off device (8, 14-17) for the incremental division elements (18) likewise in each relative position of the scanner unit (6) to the ruler (1) produces an incremental measurement signal.