Nikon DTM-502 Series Instruction Manual page 18

2) Using Optical Plummet
• Carry out the "CHECKING AND ADJUSTMENT of Optical
NOTE
Plummet" (p.4-2) when the centering operation is performed at a
position higher than the station point.
• For high accuracy, carry out the "CHECKING AND ADJUSTMENT
of Optical Plummet" (p.4-2) before the centering operation.
(1) Place the instrument on the tripod head.
Insert the tripod mounting screw into the
center hole of the instrument's base plate and
tighten.
(2) Looking through the optical plummet, align
the station point image with the center mark
of the reticle by turning the leveling
screws.
(3) While supporting the tripod head with one
hand, loosen the tripod leg clamps and adjust
the lengths of the legs to center the air bubble
in the circular level. Then tighten the tripod
leg clamps.
(4) Using the plate level proceed to the leveling
procedures described in the next section
"Leveling".
(5) Looking through the optical plummet,
reconfirm that the station point image is still
centered in the reticle mark
(6) If the slight displacement is detected, loosen
the tripod mounting screw and correct the
instrument's positioning with direct
movement (not rotational). If the
displacement is major, repeat Steps from (2).
.
2
2-9