• Without turning the instrument, position it close to wall B by
moving the tripod.
• After instrument levels, align the height of the instrument so that
the center point of laser beam is exactly on point H2 of wall B .
• Rotate the instrument by 1800(without changing the height), allow
it to level and mark the center point of the laser beam on wall A
(point H3).
• The mark of point H3 should be marked in such a way that it is as
vertical as possible (above or below) of point HI.
HI
The difference Dof both marked points HI and H3 on wall A is the
actual
deviation
The value of D (deviation) should be less than 1/4-in (6mm).
of the instrument
for the measured
-19
axis.