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10. ADJUSTMENT
Circular Vial Adjustment
1. Mount the instrument on a tripod. Center the circular vial precisely by rotating the 3
tribrach screws.
2. Rotate the instrument 180°. If the bubble is not in the center, the circular vial should
be calibrated as follow:
a. Firstly, identify the bubble moving direction, and adjust the corresponding screws to
move the bubble half of the offset.
b. Level the circular vial with the 3 tribrach screws again.
c. rotate the instrument around again to check whether the bubble is centered in
every direction. If not, please repeat the steps a & b until the bubble is centered.
Difference of Line of Sight
10.1 Method A
1. Two staffs are about 50m away, set up the tripod in the center and attach the
instrument on it.
2. Leveling the instrument
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3. The inspectations are as follow:
