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6. PREPARATION FOR MEASUREMENT
• Level and center the instrument precisely. Level and center the instrument precisely to insure the best
performance.
• Use tripods with a tripod screw of 5/8 in. diameter and 11 threads per inch, such as the Type E TOPCON
wide-frame wooden tripod. Do not use a metallic tripod.
PROCEDURE Leveling and Centering the Instrument
1. Setting up the Tripod
First, extend the extension legs to suitable
lengths and tighten the screws on their
midsections.
2. Place the instrument on the tripod head.
Place the instrument on the tripod head, lightly
tighten the centering screw.
Slide the instrument by loosening the centering
screw, place the point over the survey point, and
then tighten the centering screw.
3. Roughly Leveling the Tribrach by Using the
Tribrach circular level
Turn the leveling screws A and B and adjust the
bubble to stay at the top or bottom of the circular
level.
Turn the leveling screw C to bring the bubble to
the center of the tribrach circular level.
4. Centering with the Laser Plummet
Turn the power of this instrument ON.
Press the Tilt Setting icon.
6.4 Setting Up the Instrument
Centering screw
Leveling screw A
Leveling screw B
Leveling screw C
Tribrach circular level