Calibration of Instrument
Calibration of levelness
on it, and then turn V2 glass to face the wall directly.
at the cross of horizontal and vertical lines, and draw a vertical line along
point A.
Then point the cross point to the perpendicular line, and mark them
respectively as B, C, and D.
four points,: A, B, C, and D.
accuracy and should be repaired.
D
0
C
A
B
Perpendicular line
D
A
0
B
C
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