20
4.
Leveling by the plate level
①
Rotate the instrument horizontally by loosening the Horizontal Clamp Screw and place the plate level
parallel with the line connecting leveling screw A and B, and then bring the bubble to the center of the
plate level by turning the leveling screws A and B.
②
Rotate the instrument 90º
(100g) around its vertical axis and turn the remaining leveling screw or leveling
C to center the bubble once more.
③
Repeat the procedures
①②
for each 90º
(100g) rotation of the instrument and check whether the
bubble is correctly centered in all directions.
5. Centering by using the optical plummet
1) Set tripod
Lift tripod to suitable height, ensure equal length of three legs, spread and make tripod head parallel to the ground,
and place it right above the measurement station point. Prop up tripod on the ground and fix one leg.
2) Install instrument and collimate the point
Set instrument carefully on tripod, tighten the central connecting screw and adjust optical plummet to make the
reticle distinctly. Hold the other two unfixed legs with both hands and adjust position of these two legs through
observation of optical plummet. As it approximately aims at the station point, make all three legs fixed on the
ground. Adjust three leg screws of the instrument to make optical plummet collimate precisely to the station point
3) Use circular vial to roughly level the instrument
Adjust length of three legs of tripod, make the circular vial bubble of the instrument in the middle.