ELECTRONIC LEVEL DISPLAYING INCLINATION WITH REGARD TO INSTRUMENT LENGTH

摘要

2142097 9404888 PCTABS00030 An electronic level includes a visual scale (12) similar to a ruler scale having a number of parallel line segments (12a, 12b, 12c). The inclination of the device is shown by illuminating various of the scale line segments on either side of a central line (12a), indicating the inclination away from null. When the device is at a null only the central scale line is illuminated. Each scale line segment indicates a fraction of an inch of inclination per e.g. two feet of horizontal distance (the two feet being the level length in one version) which conforms to the normal use of such levels by building tradesmen. The level is calibrated by taking two readings with the level rotated 180· between readings. The readings are averaged and negative feedback is provided to the level sensor itself to null out any system mechanical or electrical offsets.