Nikon NPL-632, Instruction Manual

Page: 161 / 206

Field Station NPL-632 Instruction Manual 147
Checking and Adjustment 6
Checking and Adjusting the Optical Plummet
The optical axis of the plummet must be aligned with the vertical axis of the
instrument.
To check and adjust the optical plummet:
1. Place the instrument on the tripod. You do not have to level the instrument.
2. Place a thick sheet of paper marked with an X on
the ground below the instrument.
While you are looking through the optical
plummet, adjust the leveling screws until the
image of the X is in the center of the reticle
mark .
3. Rotate the alidade 180°.
If the marked image is in the same position in the
center of the reticle mark, no adjustment is
required
4. If the image is not in the same position, adjust the
optical plummet:
a. Use the supplied hexagonal wrench to turn the
adjustment screws until the image of the X is in
Position P. Position P is the center point of the
line connecting the X and the center of the
reticle mark
.
b. Repeat from Step 2 .
P