Kapro PROLASER ELECTROTA GREEN Manuel D'utilisation page 21

Horizontal Line Calibration Test
1.Set up the Rotary Laser on a level surface, between two walls
or measuring staffs that are about 30m (100ft) apart.
2. Position the laser about 0.5m (1.5ft) from 1st wall/staff.
3. Position the laser on vertical leveling side.
4. Turn on the Rotary Laser, with the Plumb up/Plumb down
projecting onto walls. Check and mark points (hA and hB) on
both walls.
5. Reposition the laser 0.5m (1.5ft) from 2nd wall/staff, pointing in
opposite direction. Check and mark points (hA' and hB') on
both walls.
6. Δ1=hA-hA'
Δ2=hB-hB'
7. The difference between Δ1 and Δ2 should be less than 6mm
(1/4 inch).
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