Automatic Leveling; Leveling Accuracy; Accuracy Check - Bosch GRL900-20HV Operating/Safety Instructions Manual

Overview
After switching on, the laser tool automatically
detects the horizontal or vertical position.
To change between horizontal and vertical
position, switch the laser tool off, reposition it
and switch on again.
After switching on, the laser tool checks
the horizontal and vertical position and
automatically levels out any unevenness within
the self-leveling range of approx. 8% (5°).
When the laser tool is inclined by more than
8% after switching on or after a position
change, leveling in is no longer possible.
In this case, the rotor is stopped, the laser
flashes and leveling indicator 3 continuously
lights up red. Reposition the laser tool and
wait for it to re-level. Without repositioning,
the laser is automatically switched off after 2
minutes and the laser tool after 2 hours.
When the laser tool is leveled in, it
continuously checks the horizontal and
vertical position. Automatic re-leveling takes
place after position changes. To avoid faulty
measurements, the rotor stops during the
leveling process, the laser flashes and the
leveling indicator 3 flashes green.
Shock-warning Function
The laser tool has a shock-warning
function; after position changes or
shock to the laser tool, or in case of ground
vibrations, it keeps the laser tool from leveling
in at changed heights, and thus prevents
errors.
To switch on the shock-warning function,
press the shock-warning button 2. The shock-
warning indicator 1 continuously lights up
green, and the shock-warning function is
activated after 30 seconds.
When the leveling-accuracy range is
exceeded after a position change of the
laser tool or when heavy ground vibrations
are detected, the shock-warning function is
actuated: The rotation stops, the laser flashes,
the leveling indicator 3 goes out and the
shock-warning indicator 1 flashes red. The
current operating mode is stored.
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Leveling Accuracy

Automatic leveling

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After the shock-warning function is actuated,
press the shock-warning button 2. The shock-
warning function is restarted and the laser
tool starts leveling. As soon as the laser tool
is leveled in (leveling indicator 3 continuously
lights up green), it starts in the stored
operating mode. Now, check the position of
the laser beam with a reference point and
adjust it, if required.
If operation is not restarted by pressing
button 2 after the shock-warning function has
actuated, the laser is automatically switched
off after 2 minutes and the laser tool after 2
hours.
To switch off the shock-warning function,
press shock-warning button 2 once, or, when
the shock warning is actuated (shock-warning
indicator 1 flashing red) press it twice. When
the shock-warning function is shut off, the
shock warning indicator 1 goes out.

Accuracy Check

Influences on Accuracy
The ambient temperature has the greatest
influence. Especially temperature differences
occurring from the ground upward can divert
the laser beam.
In addition to external influences, device
specific influences (e.g. falls or heavy impacts)
can also lead to deviations. For this reason,
check the accuracy each time before beginning
work.
The deviations play a role in excess of approx.
65 ft (20 m) distance and can easily reach two
to four times the deviation at 330 ft (100 m).
Because the largest difference in temperature
layers is close to the ground, the laser tool
should always be mounted on a tripod when
operating at distances exceeding 65 ft (20 m). If
possible, also set up the laser tool in the center
of the work area.
If the laser tool exceeds the maximum deviation
in one of the four measuring procedures, have
it checked by a Bosch customer service center.
I t
r e s p o n s i b i l i t y
periodically check the accuracy of the laser
tool as work progresses. Always check the
accuracy of the laser tool after it has been
dropped or subjected to extreme
temperatures and temperature variations.
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