User guide

Trimble M3 Total Station User Guide 117
Checking and Adjustment 10
10.2Checking 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: 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.
5. Repeat from Step 2.
P