Bosch GLL 3 X Professional Original Instructions Manual page 8

OBJ_BUCH-1772-005.book Page 8 Wednesday, August 31, 2016 2:31 PM
8 | English
Application
The measuring tool is used for determining and checking hori-
zontal and vertical lines as well as for indicating inclines. With
the two vertical laser lines that run at a 90° angle, right angles
can be indicated and checked, e.g., when dividing up spaces.
Working with Automatic Levelling (see figures A – E)
Position the measuring tool on a level and firm support, attach
it to the holder 13 or to the tripod 15.
For work with automatic levelling, push the switch for auto-
matic levelling 4 to the position. The automatic levelling
indicator 2 lights up green ( symbol/"green").
After switching on, the levelling function automatically com-
pensates irregularities within the self-levelling range of ±4°.
The levelling is finished as soon as the laser beams do not
move any more.
If automatic levelling is not possible, e.g. because the surface
on which the measuring tool is standing deviates by more than
4° from the horizontal plane, the automatic levelling indicator 2
lights up red, the laser lines flash and an audio signal sounds.
 Do not hold the measuring tool close to your ear! The
loud audio signal can cause hearing defects.
In this case, bring the measuring tool to the level position and
wait for the self-levelling to take place. As soon as the measur-
ing tool is within the self-levelling range of ±4° again, the laser
lines light up continuously, the automatic levelling indicator 2
lights up green and the audio signal is switched off.
When not within the self-levelling range of ±4°, working with
automatic levelling is not possible, because it cannot be
assured that the laser lines run at a right angle to each other.
In case of ground vibrations or position changes during opera-
tion, the measuring tool is automatically levelled in again. To
avoid errors, check the position of the horizontal and vertical la-
ser line with regard to the reference points upon re-levelling.
Working without Automatic Levelling (see figure F)
For work without automatic levelling, push the switch for
automatic levelling 4 to the position. The automatic level-
ling indicator 2 lights up red ( symbol/"red").
When automatic levelling is switched off, you can hold the
measuring tool freely in your hand or place it on an inclined
surface. The laser lines no longer necessarily run perpendi-
cular to each other.
Levelling Accuracy
Influences on Accuracy
The ambient temperature has the greatest influence. Espe-
cially 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 the tripod
15 and placed in the centre of the working area.
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 be-
ginning work.
1 609 92A 30A | (31.8.16)
First, check both the height as well as the 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, a free measuring distance of 5 m on a firm sur-
face between two walls A and B is required.
– Mount the measuring tool onto a tripod or place it on a firm
and level surface close to wall A. Switch on the measuring
tool. Select cross-line operation with automatic levelling.
A
5 m
– Direct the laser cross against the close wall A and allow the
measuring tool to level in. Mark the centre of the point
where the laser lines cross each other on the wall (point I).
A
180˚
– Turn the measuring tool by 180°, allow it to level in and
mark the cross point of the laser lines on the opposite wall
B (point II).
– Without turning the measuring tool, position it close to
wall B. Switch the measuring tool on and allow it to level in.
A
– Align the height of the measuring tool (using a tripod or by
underlaying, if required) in such a manner that the cross
point of the laser lines is projected against the previously
marked point II on the wall B.
B
B
B
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