HEDÜ NA24 Mode D'emploi page 5

Move and reset the instrument at a distance of 1~2 meter from rod A (see
picture H).Level the instrument like it is described in point 2 and 3. Take the
reading of rod A and note the measured value as a2. Then take reading of
rod B and note the measured value as b2. If I(a2-b2)-(a1-b1)I << 3mm, the
instrument is in perfect state, if not the zero position must be adjusted.
H
9
8
7
6
a2
5
4
3
2
A
1
5.4 Adjust zero position
As indicated in picture H, set the instrument in direction to staff B, take off
the eyepiece cap. Manupulate with the offered adjusting pin to take reading
b3 on the point of rod B b3 = a2 - h. (Indicated in picture I).
Repeat the above steps until I(a1-b1)-(a2-b2)I < 3mm.
I
d
9
8
7
6
b2
5
4
b3
3
2
1
B
Adjusting pin
h
05