Automatic Levelling; Accuracy Check Of The Measuring Tool - Bosch GRL 400 H Professional Originalbetriebsanleitung

18 | English
tip of the "laser beam below centre line" direction
indicator (c) is shown.
Laser receiver centred: If the laser beam hits the reception
area (18) at the height of the centre mark (17), then the
centre line indicator (e) appears in the display.
If the audio signal is switched on, a continuous signal
sounds.
Laser Beam Indicator Audio Signal
The position of the laser beam on the reception area (18)
can also be indicated by an audio signal.
You can select two different volumes for the audio signal.
To switch on the audio signal or change the volume level,
push the audio signal button (15) until the required volume
level is indicated on the display. At medium volume, the au-
dio signal indicator (d) flashes on the display; at high
volume, the indicator is continuously lit. When the audio sig-
nal is switched off, the indicator goes out.

Automatic Levelling

Overview
After switching on, the measuring tool checks the horizontal
position and automatically levels out any unevenness within
the self-levelling range of approx. ±8 % (±4.6°).
During levelling, the status indicator (5) flashes green, the
laser does not rotate and flashes.
The measuring tool is levelled in as soon as the status
indicator (5) lights up green continuously and the laser lights
up continuously. After levelling is completed, the measuring
tool automatically starts in rotational operation.
When the measuring tool is out-of-level by more than 8 %
after switching it on or after a position change, levelling in is
no longer possible. In this case, the rotor is stopped, the
laser flashes and the status indicator (5) continuously lights
up red.
Reposition the measuring tool and wait for it to re-level.
Without repositioning, the laser is automatically switched off
after 2 minutes and the measuring tool after 2 hours.
If the measuring tool is levelled, it constantly checks the level
position. Re-levelling is automatically performed if there are
any position changes. To avoid faulty measurements, the ro-
tor stops during the levelling process, the laser flashes and
the status indicator (5) flashes green.
Shock-warning function
The measuring tool has a shock-warning function. After posi-
tion changes or shock to the measuring tool, or in case of
ground vibrations, it keeps the measuring tool from levelling
in at changed positions, and thus prevents errors caused by
a change in the measuring tool's position.
Activating the shock warning: After switching on the meas-
uring tool, the shock-warning function is switched on when
factory set (the shock warning indicator (3) lights up green).
The shock warning is activated approx. 30 seconds after
switching on the measuring tool or switching on the shock-
warning function.
1 609 92A 73P | (13.01.2022)
Shock warning actuated: If the levelling-accuracy range is
exceeded when changing the position of the measuring tool
or a severe knock is registered, the shock warning will be ac-
tuated. The laser will stop rotating, the laser beam will flash,
the status indicator (5) will go out and the shock-warning
indicator (3) will flash red.
When the shock warning has actuated, briefly press the on/
off button (4). The shock-warning function is restarted and
the measuring tool starts the levelling. As soon as the meas-
uring tool is levelled in (the status indicator (5) lights up
green continuously), it automatically starts in rotational op-
eration.
Now check the position of the laser beam at a reference
point and, if necessary, correct the height of the measuring
tool.
If the function is not restarted by pressing the on/off
button (4) after the shock warning has actuated, the laser is
automatically switched off after 2 minutes and the measur-
ing tool after 2 hours.
Switching off the shock-warning function: To switch the
shock-warning function off or on, press the on/off button (4)
for 3 seconds. When the shock warning has actuated (shock
warning indicator (3) flashes red), firstly press the on/off
button briefly, and then again for 3 seconds. When the shock
warning is switched off, the shock warning indicator (3) will
go out.
If the shock-warning function has been switched on, it will be
activated after approximately 30 seconds.
The shock-warning function setting is stored when switching
off the measuring tool.

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.
In order to minimise thermal influences resulting from heat
rising from the floor, it is recommended that you use the
measuring tool on a tripod. In addition, position the measur-
ing tool 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.
Should the measuring tool exceed the maximum deviation
during one of the tests, please have it repaired by a Bosch
after-sales service.
Check the levelling accuracy
For a reliable and precise result, it is recommended that you
check the levelling accuracy on a free measuring distance
of 30 m on firm ground in front of a wall. Carry out a com-
plete measuring procedure for each of the two axes.
– Mount the measuring tool on a tripod at a distance
of 30 m to the wall or place it on a firm and level surface.
Switch on the measuring tool.
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