Johnson Theodolites 40-6936 Manual De Instrucciones página 26

8863H-All_Manuals 3/19/15 3:25 PM Page 26
• Rotate the instrument 180 degrees and check
if the bubble remains centered. If the bubble
is centered, the adjustment is complete. If
not, repeat the steps until the bubble is
centered when the instrument is at any
position.
Check and Calibrate The Circular Vial
Checking
If the circular vial is centered correctly after leveling the instrument
by the tubular vial, then no further calibration is necessary. If not,
proceed with the following calibration.
Calibrating
There are three adjusting screws on the bottom
of the circular vial. When calibrating, loosen the
screw opposite to the bubble's moving
direction (one or two), and then tighten the
screws along the bubble's moving direction to
center the bubble. The tightening of these three screws should
be consistent.
Perpendicularity of Vertical Crosshair Reticle of Telescope
Checking
• Mount the instrument on the tripod and level it carefully.
• Set a target point, A, 50 meters away from the instrument, aim the
telescope at point A .
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Circular Vial
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