Measuring Methods; Calibration Levelling Bubble - LaserLiner AL 22 Mode D'emploi

Important: Remaining inclinations
of the crosshairs which are left
after the levelling bubble has been
centred will be eliminated by the
compensator. The compensator,
however, will not eliminate any
inclinations caused by faulty
calibration of the levelling bubble
or the crosshairs. Therefore, the
positions of both gadgets should be
checked before measuring (see
calibration).
Determination of a height
difference
1. Place instrument halfway bet-
ween the positions of staves A and
B. Aim instrument at staff A and
read the value of the graduation of
the staff at your crosshairs (A =
140 cm). Turn instrument towards
rod B and get the reading from the
graduation (B = 90 cm).
140 cm
A
½L
2. The difference (A-B) results in a
height difference
H = +50 cm between B and A. The
B
H
½L

Measuring methods

point B is 50 cm higher than point
A. The difference H turns negative
when point B is lower than point A.
Important: A slight deviation of the
crosshairs does not cause any misrea-
dings provided the instrument has
been placed approx. midway between
the positions of the two staves A and
B.
Staving out a height
B
A
x
H=120 cm
1. Place the staff on a point with a
known height. Read value (A) from
the graduation (A = 90 cm) Add the
read value to the height of the
known point. Now deduct the
height of the
point to be staved out from this
value (height on the crosshairs).
H + A - x = B
2. Keep moving the levelling staff
vertically until the calculated
difference B can be read on the
graduation. Afterwards, mark the
height of the toe of staff.
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ENGLISH