| 摘要 |
The invention relates to a length measuring device having: a measuring slide (4); a linear guide (2) on the outside of which the measuring slide is movably mounted; an internal slide (6), which is movably mounted in the interior of the guide; a magnetic coupling designed such that the internal slide follows every motion of the measuring slide along the guide; a sound source (8); a sound receiver (8); and a control unit (10) connected thereto for evaluating the output signals of the sound receiver (8), in order to determine the transit time of a first sound signal reflected from the internal slide (6) and calculate the position of the internal slide along the hollow profile therefrom and in order to detect an additional reflected sound signal, reflected at a known point along the hollow profile, in the output signal of the sound receiver (8) and to allow the transit time of said signal to be entered as a reference measurement into the calculation of the position of the internal slide. |
