Establishment of horizontal line of sight to determine the height difference between two points on the ground. The main parts are telescope, tube level (or compensator), vertical axis, base, foot screw. According to the structure is divided into micro-tilt level, automatic leveling level, laser level and digital level (also known as electronic level). According to the precision, it is divided into precision level meter and common level meter. Level meter application classification:
Level meter is suitable for level measurement instrument, at present our country level meter is according to the instrument can achieve per kilometer round-trip measurement of the number of elevation difference in the accidental error in the precision index of the division, *** divided into 4 levels.
Leveling instrument models start with DS, respectively, for the "earth" and "leveling instrument" of the Hanyu Pinyin F a letter, usually written omitting the letter D. Subsequently, 05.", "1", "3", "10" and other numbers indicate the precision of the instrument. S3 level and S10 level are also known as ordinary level, used in China's national third and fourth level and ordinary level measurement, S05 level is also known as ordinary level. The S05 and S1 levels are called precision levels, which are used for national first and second class precision level measurement:
Leveling instrument model DS0 5 DS1 DS3DS10
Kilometer round-trip elevation difference in median accidental error ≤ 0.5mm ≤ 1mm ≤ 3mm ≤ 10mm
Main use of the instrument is for national first class level measurement and seismic monitoring. National Second Class Level Measurement and Precision Level Measurement National Third and Fourth Class Level Measurement and General Engineering Level Measurement General Engineering Level Measurement
Circular level axis is parallel to the vertical axis (L'L'//VV);
(2) Cross filament of cross-wire dividing plate is perpendicular to the vertical axis;
(3) Tube level axis is parallel to the visual axis (LL//CC).
Leveling instrument belongs to precision measuring equipment, the instrument tuning requirements are relatively high, so these axes should meet the relationship, it is not good to discuss which is the most important online wrote (3) the most important, I think it is not reasonable to take (1), the round level is directly related to the instrument's rough level, if the relationship between the problem, the instrument can not be rough, how to start the measurement it. If this relationship is wrong, the instrument can not be rough leveled, how can we start the measurement? The cross wire dividing plate affects the reading, we bluffing is ultimately to get the data through the reading, the instrument again accurate reading deviation is too large is meaningless, so (2) also need to be as accurate as possible. Unilaterally (3) may cause a larger error, but can be completely eliminated by equalizing the distance between the front and back of the ruler,