Johnson Theodolites 40-6936 Manual De Instrucciones página 9

8863H-All_Manuals 3/19/15 3:25 PM Page 9
Preparation Before Measurement
Centering and Leveling with Laser Plummet
• Level and center the instrument precisely to ensure its best
performance.
• Extend the tripod legs to a suitable working height with equal length
legs. Spread the tripod legs and make the tripod head as level as
possible while at the same time placing the center of the tripod head
directly over the ground point. Press the leg feet firmly into the
ground and make sure the tripod legs are locked.
• Set the instrument carefully on the center of the tripod head
orientating the leveling screws centered with each tripod leg. Attach
the instrument to the tripod. Make sure the center mark is visible on
all three leveling screws (this ensures a complete leveling range).
• With the instrument turned on, turn on the laser plummet by turning
the laser plummet on/off knob clockwise. Adjust the Laser Plummet
so the laser dot hits the ground clearly. If you cannot see the laser
dot hit the ground, carefully lift two of the tripod legs, then pivot on
the third leg, carefully moving the tripod until the ground point is
within one inch of the laser dot. Press the two tripod feet back into the
ground and recheck the laser plummet alignment. Repeat if
necessary until the ground point is being hit by the laser dot.
• Now center the instrument's Circular Vial by carefully extending or
shortening the tripod leg closest to the bubble. Note: Use only two
legs. Repeat until alignment is within 6mm (1/4 inch) or less.
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