Accuracy Check Of The Measuring Tool - Bosch GLL 5-50 X Professional Manual Original

If automatic levelling is not possible, e.g. because the sur-
face on which the measuring tool stands deviates by more
than 3° from the horizontal plane, the laser beams will flash
quickly.
If this is the case, set up the measuring tool in a level position
and wait for the self-levelling to take place. As soon as the
measuring tool is within the self-levelling range of ±3°, the
laser beams will light up continuously.
In case of ground vibrations or position changes during oper-
ation, the measuring tool is automatically levelled again.
Upon levelling, check the position of the laser beams with re-
gard to the reference points to avoid errors arising from a
change in the measuring tool's position.
Working with the pendulum lock
For work with the pendulum lock, slide the on/off switch (7)
to the " On" position. The pendulum lock indicator (14)
lights up red and the laser lines continuously flash slowly.
For work with the pendulum lock, automatic levelling is
switched off. You can hold the measuring tool freely in your
hand or place it on a sloping surface. This means that the
laser beams are no longer levelled and no longer necessarily
run perpendicular to one another.

Accuracy Check of the Measuring Tool

Influences on Accuracy
The largest influence is exerted by the ambient temperature.
In particular, temperature differences that occur from the
ground upwards can refract the laser beam.
Since the temperature stratification is greatest at ground
level, you should mount the measuring tool on a tripod and
position it in the centre of the work surface, wherever this is
possible.
In addition to external influences, device-specific influences
(e.g. falls or heavy impacts) can also lead to deviations. For
this reason, check the levelling accuracy each time before
beginning work.
First check the height accuracy and levelling accuracy of the
horizontal laser line, then the levelling accuracy of the ver-
tical laser line.
Should the measuring tool exceed the maximum deviation
during one of the tests, please have it repaired by a Bosch
after-sales service.
Checking the Height Accuracy of the Horizontal Line
For this check, you will need a free measuring distance of
5 m on firm ground between two walls (designated A and B).
– Mount the measuring tool close to wall A on the rotating
platform (12) or a tripod (28), or place it on a firm, flat
surface. Switch on the measuring tool in the mode with
automatic levelling. Switch on horizontal mode and ver-
tical mode with a laser line forwards.
Bosch Power Tools
A
5 m
– Aim the laser at the closer wall A and allow the measuring
tool to level in. Mark the middle of the point at which the
laser lines cross on the wall (point I).
A
180°
– Turn the measuring tool 180°, allow it to level in and mark
the point where the laser lines cross on the opposite wall
B (point Ⅱ).
– Position the measuring tool – without rotating it – close to
wall B, switch it on and allow it to level in.
A
– Align the height of the measuring tool (using the tripod or
by placing objects underneath as required) so that the
point where the laser lines cross exactly hits the previ-
ously marked point Ⅱ on wall B.
A
d
English | 9
B
B
B
B
180°
1 609 92A 4HR | (26.11.2020)