HEDÜ NA24 Mode D'emploi page 4

Adjust the other half of the displacement by screw wrench and center the
bubble by the two adjusting screws (see picture F). Repeat the above steps
until the bubble does not vary with the instrument body (see picture D).
F
5.3 Check of zero position
Set up two rods A, B facing each other at a distance of 50 meter and place
the instrument in middle of them.
Level the instrument like it is described in point 2 and 3. Take the reading of
rod A and note the measured value as a1. Then take reading of rod B and
note the measured value as b1. The height differences between A and B is
h =a1 - b1 (see picture G).
G
9
8
7
6
a1
5
4
3
2
1
A
04
d
d d
Adjusting screws
9
8
7
6
5
d
4
3
2
1
d
b1
B
h