Abstract: A scanning unit that includes a radiation source that emits electromagnetic radiation, which is used to scan a scale of a position measuring system, wherein the radiation source includes electrical connection elements. The scanning unit further including a holder upon which the radiation source is fixable, wherein the holder includes electrical conductor elements that electrically contact the electrical connection elements. The electrical conductor elements of the holder and the electrical connection elements of the radiation source form a guide on which the radiation source is movable along an adjustment path relative to the holder while maintaining electrical contact between the electrical connection elements and the electrical conductor elements. Maintaining electrical contact enables positioning the radiation source at various positions along the adjustment path on the holder wherein the electrical connection elements are in electrical contact with the electrical conductor elements.

Abstract: An annular body has an angle scale for measuring the rotational position of a machine part about an axis, the body having recesses and projections on its inner circumference, and at least one of the recesses being suited for a form-locking rotatably fixed attachment on the machine part. The sum of the central angles, which are respectively defined by starting points and end points of the projections is smaller than the sum of the central angles, which are respectively defined by the starting points and end points of the recesses. Such a body on a high-speed shaft of a machine tool may be used for measuring the rotational position of the shaft.

Abstract: An annular body has an angle scale for measuring the rotational position of a machine part about an axis, the body having recesses and projections on its inner circumference, and at least one of the recesses being suited for a form-locking rotatably fixed attachment on the machine part. The sum of the central angles, which are respectively defined by starting points and end points of the projections is smaller than the sum of the central angles, which are respectively defined by the starting points and end points of the recesses. Such a body on a high-speed shaft of a machine tool may be used for measuring the rotational position of the shaft.