Automatic Levelling - Bosch GLL 3-80 P Professional Manual Original

14 | English
without laser receiver. When the pulse function is switched
off, the pulse-function indicator 4 is deactivated.

Automatic Levelling

Working with Automatic Levelling
Position the measuring tool on a level and firm support, attach
it to the holder 19 or to the tripod 22.
When working with automatic levelling, push the On/Off
switch 7 to the " on" position.
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 stands deviates by more than 4°
from the horizontal plane, the laser lines begin to flash rapid-
ly. When the audio signal is activated, a fast-beat signal
sounds for 30 s (maximum). This alarm is deactivated within
10 s after switching on, in order to allow adjustment of the
measuring tool.
Set up the measuring tool in level position and wait for the
self-levelling to take place. As soon as the measuring tool is
within the self-levelling range of ±4°, all laser beams light up
continuously and the audio signal is switched off.
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
For working without automatic levelling, slide the On/Off
switch 7 to the " on" position. When automatic levelling is
switched off, indicator 6 lights up red and for the first 30 s la-
ser beams flash slowly.
When automatic levelling is switched off, you can hold the
measuring tool freely in your hand or place it on an inclinded
surface. The laser lines no longer necessarily run vertical to
each other.
Levelling Accuracy
Influences on Accuracy
The ambient temperature has the greatest influence. Espe-
cially temperature differences occurring from the ground up-
ward can divert the laser beam.
Because the largest difference in temperature layers is close to
the ground, the measuring tool should always be mounted on a
tripod when measuring distances exceeding 20 m. If possible,
also set up the measuring tool in the centre of the work 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.
Firstly, check the levelling accuracy of the horizontal laser line
and then the levelling accuracy of the vertical laser lines.
Should the measuring tool exceed the maximum deviation
during one of the tests, please have it repaired by a Bosch af-
ter-sales service.
1 619 929 L95 | (29.11.12)
Checking the Horizontal Levelling Accuracy of the Lateral
Axis
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 to operation with automatic levelling. Select the oper-
ating mode in which a horizontal laser plane as well as a
vertical laser plane in front of the measuring tool are gener-
ated.
A
– Direct the laser against the close wall A and allow the meas-
uring tool to level in. Mark the centre of the point where the
laser lines cross each other at wall A (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
5 m
B
B
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