Bosch GPL 5 Professional Notice Originale page 14

OBJ_BUCH-815-001.book Page 14 Thursday, October 2, 2008 9:04 AM
14 | English
Levelling Accuracy
Influences on Accuracy
The ambient temperature has the greatest in-
fluence. Especially temperature differences
occurring from the ground upward can divert
the laser beam.
As thermal fluctuation is largest close to the
ground, the measuring tool, if possible, should
be mounted on a commercially available tripod
and placed in the centre of the working area.
Apart from exterior influences, device-specific
influences (such as heavy impact or falling
down) can lead to deviations. Therefore, check
the accuracy of the measuring tool each time
before starting your work.
Should the measuring tool exceed the maximum
deviation during one of the tests, please have it
repaired by a Bosch after-sales service.
When the levelling accuracy of the horizontal
laser beams for the lateral and longitudinal axis
is within the maximum allowable deviation, then
the levelling accuracy for the plumb beams
(vertical axis) is thus also checked.
Checking the Horizontal Levelling Accuracy of
the Lateral Axis
A free measuring distance of 20 m on a firm sur-
face in front of a wall is required for the check.
– Mount the measuring tool onto the holder or
a tripod, or place it on a firm and level sur-
face at a distance of 20 m to the wall. Switch
the measuring tool on.
1 609 929 S07 | (2.10.08)
2 0
m
– Direct one of the two lateral laser beams,
that run alongside the lateral axis of the
measuring tool, at the wall. Allow the meas-
uring tool to level in. Mark the centre of the
laser beam on the wall (point I).
d
– Rotate the measuring tool by approx. 180°
without changing its height. Allow it to level
in and mark the centre point of the other lat-
eral laser beam on the wall (point II). Take
care that point II is as vertical as possible
above or below point I.
– The difference d of both marked points I and
II on the wall results in the actual height de-
viation of the measuring tool alongside the
lateral axis.
On the measuring distance of 2 x 20 m = 40 m,
the maximum allowable deviation is:
40 m x ±0.3 mm/m = ±12 mm.
Thus, the difference d between points I and II
may not exceed 12 mm (max.).
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