C
A
a2
x
x
a1
13) Measure the distances:
14) The difference |Δa – Δb| should be no more than 3 mm,
otherwise send the laser to a qualified technician for repair.
15) Repeat the procedure for top horizontal beam.
2 m
Figure 4
Δa= |a2-a1|
Δb= |b1-b2|
180°
B
x
b1
b2
x
0.5 m
17