第一节 微倾式水准仪的检验与校正
　　 水准仪的主要轴线有：照准部水准管轴LL，望远镜视准轴CC，圆水准器轴L’L’，仪器竖轴W。根据水准测量的原理，水准仪必须提供一条水平视线，这是水准仪构造的—个极为重要的条件，为此水准仪各轴线应满足：
　　 (1)水准管轴应平行于视准轴(LL∥CC)。
　　 (2)圆水准器轴应平行于仪器竖轴(L’L’∥W)。
　　 (3)十字丝的中丝(横丝)应垂直于仪器竖轴。
　　 其中(1)为主要条件，(1)、(3)两个为次要条件。这些条件在仪器出厂时已经过检验与校正。但由于仪器长期使用以及在搬运过程中可能出现的振动和碰撞等原因，使各轴线之间的关系发生变化，若不及时检验校正，将会影响测量成果的质量。所以，在进行正式水准测量工作之前，应首先对水准仪进行严格的检验和认真的校正。
　　 仪器检校的原则是：各项检校项目顺序应遵循前面的检校项目不受后面检校项目的影响。
　　 仪器检校的注意事项：
　　 (1)仪器的检校下作是一项难度较大的细致工作，经严格检验确认需校正时才可进行校正。
　　 (2)检验与校正的顺序严格按上述步骤进行，不能颠倒。
　　 (3)校正时各校正螺钉应先松后紧，松紧适度，校正结束时，各螺钉应处于稍紧状态。
　　 (4)需用校正针时，校正针的粗细应与校正螺钉孔经相适应，否则，会损坏校正螺钉孔径。
　　 一、圆水准器的检验与校正
　　 1．检验目的
　　 保证圆水准器轴L’L’，平行于仪器竖轴W。
          2．检验方法

          首先用脚螺旋使圆水准器气泡居中，此时圆水准器轴L'L'处于竖直位置，如图(17-1-1a)所示，若仪器竖轴VV与L'L'不平行，且交角为a,则竖轴偏离竖直方向a,将仪器绕竖轴VV旋转180°，如图(17-1-1b)所示，此时位于竖轴左边的圆水准器轴L'L'不但不竖直，而且与铅垂线的交角为2a,显然气泡不居中，说明仪器不满足L'L'//VV的几何条件，需要校正。

3．校正方法
　　 首先稍松位于圆水准器下面中间部位的固紧螺钉，然后用拨针调整其周围的三个校正螺钉，使气泡向居中位置移动偏离量的一半，如图17-1-1c)所示。此时，圆水准器轴与竖轴平行。然后再用脚螺旋整平，使圆水准器气泡居中，竖轴w就与圆水准器轴L’L’同时处于竖直位置，如图17-1-1d)所示。校正工作一般需反复进行，直至仪器旋转到任何位置时圆水准器气泡均居中为止。校正时应按先松后紧的原则，即要旋紧一校正螺钉，必先略松其对应的螺钉，防止旋紧时导致螺钉滑丝或断裂。其次，校正完毕，应拧紧各校正螺钉，使校正好的圆水准器固定不动。
　　 二、十字丝的检验与校正
　　 1．检验目的
　　 保证十字丝横丝垂直于仪器竖轴W。
　　 2．检验方法
　　 首先安置好仪器，用十字丝横丝对准一个明显的点状目标M，如图17-1-2a)所示。然后固定制动螺旋，转动水平微动螺旋。如果目标点M沿横丝移动，如图17-1-2b)所示，则说明横丝垂直于竖轴W，不需要校正。否则，如图17-1-2c)和d)所示，则需要校正。
　　 3．校正方法
　　 校正方法因十字丝分划板装置的形式不同而异。多数仪器可直接用螺丝刀松开分划板的固定螺钉，转动分划板，改正偏离量的一半，即满足条什。此项条件校正也需要反复进行，最后得出正确结果。
 

Section micro-tilting Level Examination and Correction
Levels of the main axes are: the Department awarded the standard tube axis LL, the telescope collimation axis CC, circular bubble shaft L'L ', instrument vertical axis W. According to the principle of leveling, leveling must provide a level of attention, which is constructed water level - an extremely important condition, for leveling the axis should be met:
(1) standard tube axis should be parallel to the collimation axis (LL ∥ CC).
(2) The circular bubble shaft should be parallel to the instrument vertical axis (L'L '∥ W).
(3) cross wire in the wire (horizontal wire) should be perpendicular to the instrument vertical axis.
One (1) as the main condition, (1), (3) 2 as a secondary condition. These conditions, when the instrument has been factory tested and correction. However, long-term use as well as in handling equipment that may arise during the vibration and collision and other reasons, so that the relationship between the various axes of change, if not timely inspection and correction, will affect the measurement of quality results. Therefore, before making a formal standard of survey work should be the first rigorous test of the water level and careful calibration.
Instrument calibration principle is: the order of the calibration project in front of calibration to be followed later in the project does not affect the calibration project.
Instrument calibration Precautions:
(1), mainly as the instrument calibration is a difficult and detailed task, after strict testing carried out only at the time recognized the need for calibration correction.
(2) The order of testing and calibration carried out in strict accordance with the above steps can not be reversed.
(3) correction, the correction should loose screws after the tight, elastic moderate correction at the end of the screw should be slightly tight in the state.
(4) The need to use correct needle, needle thickness correction should be corrected by the corresponding screw holes, otherwise, may damage the calibration screw aperture.
1, round the standard of testing and calibration device
1. Test Objective
Ensure that the standard round shafts L'L ', parallel to the instrument vertical axis W.
           2. Testing methods

           First, screw with their feet so that circular bubble bubble center, this time round the standard shafts L'L 'in the upright position, shown in Figure (17-1-1a) shows that if the instrument vertical axis VV with the L'L' is not parallel , and the inclination of a, then the vertical axis deviated from the vertical direction of a, the instrument around the vertical axis VV rotate 180 °, shown in Figure (17-1-1b) shows, this time in the vertical axis on the left of the circular bubble axis L ' L 'not only did not vertical, but also with the plumb line of the obliquity of 2a, is clearly the bubble is not centered, indicating instrument does not meet the L'L' / / VV geometric conditions, needs correction.



3. Correction
First, a little loose in the circular bubble below the middle of the solid tight screws, and then call around the 3-pin to adjust its calibration screws, so that air bubbles move to the center position deviation of the half, shown in Figure 17-1-1c) as shown. At this point, circular bubble axis and vertical axis parallel to. And then screw leveling feet, so that circular bubble bubble center, vertical axis w with circular bubble axis L'L 'at the same time in the upright position, shown in Figure 17-1-1d) as shown. Calibration work generally required to be repeated until the apparatus rotated to any position in the circular bubble until the bubble tops. Calibration should be tight after the first loose the principle that the screws should be tightened up and a correction, one must first of its corresponding screws slightly loose, tighten to prevent the wire when the lead screw slide or rupture. Secondly, the calibration is completed, the correction should be tightening screws, so that a good correction circular bubble stationary.
Second, cross-examination and correction of silk
1. Test Objective
Ensure that cross wire cross wires perpendicular to the instrument vertical axis W.
2. Testing methods
First, a good placement equipment, with the cross wire cross wires aligned an obvious point targets M, shown in Figure 17-1-2a) as shown. Then the fixed brake screw, rotate the level of micro-screw. If the target point M along the horizontal wire movement, shown in Figure 17-1-2b) as shown, then cross-wires perpendicular to the vertical axis W, without correction. Otherwise, as Figure 17-1-2c) and d) below, you need to correct.
3. Correction
Correction methods due to cross-wire reticle in the form of installations vary. Most equipment can be directly reticle with a screwdriver loosen the screw, turn reticle to correct the deviation of the half, or even to meet the article. This condition also need to be repeated correction and finally reach the right result.