Accuracy Check - David White 4200H Owner's Manual

The ambient temperature has
the greatest influence. Especially
temperature differences occurring
from the ground upward can divert
the laser beam. The deviations play a
role in excess of approx. 65-ft (20m)
measuring distance and can easily
reach two to four times the deviation
at 330-ft (100m). Because the largest
difference in temperature layers is
close to the ground, the instrument
should always be mounted on a
tripod when measuring distances
exceeding 65-ft (20m). If possible,
also set up the instrument in the
center of the work area.
Checking the Leveling Accuracy
Apart from exterior influences,
X1
device-specific influences (such as
heavy impact or falling down) can
lead to deviations. Therefore, check
the accuracy of the instrument each
time before starting your work. A
free measuring distance of 165-ft
165-ft (50 m)
(50m) on a firm surface is required for
the check. A reversal measurement
must be carried out over both axes X
Y1
and Y (each positive and negative; 4
complete measurements).
– Mount the instrument in the
horizontal position onto a tripod or
place it on a firm and level surface
165-ft (50 m)

ACCURACy CHECK

– After the leveling, mark the center of
– Rotate the instrument by 180°,
H1
H1
– The difference D of both marked
H1
The value of D (deviation) should be
less than 5/16-in (8mm).
H1
-13-
near wall. Switch the instrument
on. Position the X-axis to aim to a
wall or target plate.
X1
Y1
the laser beam on wall (point H1).
allow it to level in and mark the
center point of the laser beam on
the wall (point H2).
180°
X2
4250HV 90° 45°
180° 10°
RPM
A
180°
Y2
points H1 and H2 on wall is the
actual deviation of the instrument
1.5-ft
(0.5 m) for the measured axis.
A
165-ft (50 m)
165-ft (50 m)
D
B
165-ft (50 m)
100-ft (30 m)
D
B
165-ft (50 m)
H1
H1
H1
H2
H1
H1
H2
H3
H2
H1