Checking and adjusting of the line-of-sight
H=1.832
H=1.616
δ
I
1
A
d
With the circular bubble centred
and adjusted, the line of sight
should be horizontal.
Checking (see example):
1. Choose a distance of appr.
30 m within a gentle terrain.
2. Set up a staff at both final
points (A, B).
3. Set up the instrument at point
I
(halfway between A and B,
1
just pass it down) and centre
the bubble.
RUNNER 20/24-1.0.1en
actual=1.604
δ
B
A
d
4. Read both staffs.
reading on A
reading on B
∆H = A - B
5. Set up the level about 1 m
from staff A
6. Read staff A (eg.: 1.604 m)
7. Find nominal reading B;
eg.: Reading A - ∆H =
1.604 m - 0.216 m = 1.388 m
8. Read staff B, compare
nominal-/actual- reading.
δ
nominal
I
=1.388
2
B
= 1.832 m
= 1.616 m
= 0.216 m
20
When the difference
nominal-/actual- reading
is more than 3 mm the line of
sight must be adjusted.
1. Turn the adjusting srew until
the midle hair gives the
required reading
(eg. 1.388 m).
2. Check line of sight again.
Checking and adjusting