Bosch GTL 3 Professional Manual Original página 16

16 | English
Never leave the measuring tool unattended when
u
switched on, and ensure the measuring tool is
switched off after use. Others may be blinded by the
laser beam.
Deactivating the automatic shut-off function
The measuring tool automatically switches itself off after
30 min of operation.
To deactivate the automatic shut-off function, press and
hold the on/off button (3) for 3 s when switching on the
measuring tool. If the automatic shut-off function is de-
activated, the laser lines will flash briefly when the meas-
uring tool is first switched on.
To activate the automatic shut-off function, switch the
measuring tool off and then switch it back on again by
pressing the on/off button (3) briefly. Once the measur-
ing tool is switched back on, the laser lines will not flash.
Accuracy Check of the Measuring Tool
Influences on Accuracy
The largest influence is exerted by the ambient temper-
ature. In particular, temperature differences that occur
from the ground upwards can refract the laser beam.
For this reason, place the measuring tool as close as pos-
sible to the work surface and secure it with the base run-
ning as near parallel to the work surface as possible.
In addition to external influences, device-specific influ-
ences (e.g. falls or heavy impacts) can also lead to devi-
ations. For this reason, check the angle accuracy each
time before beginning work.
Should the measuring tool exceed the maximum devi-
ation during one of the tests, please have it repaired by a
Bosch after-sales service.
Checking the angle accuracy between the 0° and 90°
laser lines
For this check, you will need a clear area of firm, level
ground measuring approx. 10 × 5 m.
– Place the measuring tool in one corner of the measur-
ing area. Switch the measuring tool on and set it up so
that the 0° laser line runs down the long side of the
measuring area and the 90° laser line runs down the
short side of the measuring area.
1 609 92A 4HU | (16.01.2019)
10 m
– Mark the point where the two laser lines intersect on
the ground (point Ⅰ). Make another mark in the centre
of the 0° laser line at a distance of 5 m (point Ⅱ) and
at a distance of 10 m (point Ⅲ).
– Position the measuring tool (without rotating it) at a
distance of 5 m so that the intersection point of the
laser lines meets point Ⅱ and the 0° laser line runs
through point Ⅲ. Mark the centre of the 90° laser line
at a distance of 5 m (point Ⅳ).
– Rotate the measuring tool through 90° so that the
centre of the 0° laser line runs through point Ⅳ. The
laser lines must still intersect at point Ⅱ. At a distance
of 5 m, mark the centre of the 90° laser line as point Ⅴ
as close as possible to point Ⅰ.
– The discrepancy d between points Ⅴ and Ⅰ is the ac-
tual deviation of the 0° and 90° laser lines from the
right angle.
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