Johnson Level & Tool Mfg. 40-6936 User Manual

Page 9

Preparation Before Measurement

Centering and Leveling with Optical 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).

• Adjust the Optical Plummet Eyepiece to focus the bullseye. Adjust the

Optical Plummet telescope focus to see the ground clearly. If you can
not see the ground point while looking through the optical plummet,
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 reticule. Press the two tripod feet back into the ground and
recheck the optical plummet alignment. Repeat if necessary until the
ground point can be seen in the optical plummet field. Complete the
alignment by turning the leveling screws (you will not be level but
you are pointed correctly).

• Now center the instruments Circular Vial by carefully extending or

shortening the tripod legs closest to the bubble. Note: Use only two
legs. Repeat until alignment is within 6mm (1/4 inch) or better.

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