Using The Instrument - CST/BERGER SAL20N Instruction Manual

After doing any job using any instrument, it is advised that you check your work. To check your
work, set up the instrument in a different location from the place where you originally set up
(approx. 16 m) and reshoot a few of your original targets. The new readings should agree with
the first readings.
If the new readings do not agree, you should have the instrument checked by a CST/berger
Authorized Repair Center, or try the Line-of-sight adjustment.

USING THE INSTRUMENT

Setting up the instrument and centering the bubble
1. Set up the tripod and attach the level using the tripod mounting screw.
2. Adjust the tripod legs until the tripod head is roughly level. Center the bubble within the vial
by turning the leveling screws as shown in Fig. 2.
2a – Turn screws A and B to move the bubble to the right side.
2b – Turn screw C to center the bubble.
Focusing the instrument
1. Focus the cross hairs (Fig. 3) by pointing the telescope towards a bright background or
holding a white sheet of paper in front of the objective lens, then turning the eyepiece until
the cross hairs are sharp and black.
2. Focus the telescope by locating a target, such as a leveling rod, using the optical peep sight.
Looking through the eyepiece, use the focusing knob to bring the target into sharp focus.
Center the vertical hair within the target using the horizontal drive knobs on either side of the
instrument.
Reading measurements using a leveling rod
Height reading
Read the rod where it is intersected by the horizontal hair. For example, the height reading in Fig. 4
(Fig. 4/a) is 2.0 ft (1,195 m).
Distance measurement
Read the rod where it is intersected by the upper and lower stadia hairs; in Fig. 4 (Fig. 4/a) these
readings are at 1.9 ft and 2.1 ft (1,352 m and 1,038 m). The stadia ratio is 1:100; therefore, the
distance from the instrument to the rod is: (2.1 - 1.9) x 100 = 20 feet - Fig. 4/a (1,352 –1,038) x 100 = 31,41 m.
Angle measurement
As shown in Fig. 5, sight point A and rotate the horizontal circle until the reference mark is on "0".
Rotate the level and sight point B; the reference mark will indicate the angle between A and B.
4 • PAL/SALN AutoLevel