Tests and adjustments of theodolite

1st verification: the axis of the cylindrical level UU (Fig. 1, a) on the alidade of the horizontal circle should be perpendicular to the vertical axis of rotation of the JJ instrument.

Set the level along two lifting screws and, rotating them in different directions, bring the bubble to the zero-point (in the middle of the ampoule). Rotate theodolite 180 °. If the level bubble has shifted from the zero-point to the side by more than 1... 1.5 divisions, then the condition is not satisfied.

Adjustment. Bubble to the middle of the level ampoule with correctional screws for half the deviation arc, for the remainder of the deviation - with the same lifting screws. After adjustment it is necessary to perform verification again.

2nd verification: the vertical bar of the grid (see Fig. 2, a) should be perpendicular to the axis of rotation of the TT pipe.

Bring the edge of the horizontal grid line to a point. Using the guide screw of the horizontal circle alidade, turn the pipe so that the point is at the other edge of the stroke. If a point when “rolling” on a stroke comes down from the stroke, then the condition is not satisfied.

Adjustment. Unscrew the mesh safety cap, loosen the four screws under the screwdriver. Hand rotate the mesh holder half the deviation of the horizontal bar from the point. Fasten the screws, check again.

3rd verification: the telescope's centering axis VV should be perpendicular to the axis of rotation of the TT tube.

With two positions of the device - “circle left” (CL) and “circle right” (KP) - direct the center of the grid of strokes to the same point and count the samples along the horizontal circle. Calculate the value of collimation error C using sample values ​​using the formula:

C = [(CL ± 180 °) - KP] / 2,

where KL and KP are the horizontal circle readings when the theodolite is in position, respectively, KL and KP.

C = [(1005 '+ 1800) - 1810 04'] / 2 = 30 ''? 1 'In our case, verification is performed.

If the collimation error exceeds the double accuracy (± 1 ') of taking the reference on the microscope scale, then the verification condition is not satisfied. Verification is performed by two techniques at two different points, as a result, the average collimation error is calculated.

Adjustment. In the second method, a sample that is free from the influence of a collimation error is calculated on the average for the CP. This countdown is set on a horizontal circle. Rotating with the help of the pin the side correction screws of the grid, combine the center of the grid with the point of observation. Vertical screws slightly loosen before adjustment.

4th verification: the axis of rotation of the TT telescope should be perpendicular to the vertical axis of rotation of the JJ instrument.

When the CL device is in position, the center of the grid is directed to a high point, the pipe is lowered onto a horizontally laid rail (ruler), and the vertical reading of the grid is read on it. The same operation is repeated at the second position of the device KP. If the samples are equal, then the condition is met. Adjustment is not performed. The condition is guaranteed by the factory. In case of non-fulfillment of the condition, the device is corrected in the workshop.