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13
• Set up the instrument about 1m away from point A. Then read staff A and staff B as “a2”
and “b2” (fig. 13).
• Then you can get the logical value b2’ = a2 -
Δ
H , b2’ is the height b2 should be
• When the difference between b2 and b2’ is more than 3mm, the line of sight
must be adjusted.
A
B
a2
δ
b2
b2’
1m
Fig. 13
△
H