Operating Modes; Automatic Levelling - Bosch Professional GCL 25 Manual Original

OBJ_BUCH-1546-004.book Page 13 Wednesday, March 2, 2016 2:10 PM
 Avoid heavy impact to or falling down of the measuring
tool. Damage to the measuring tool can impair its accura-
cy. After heavy impact or shock, compare the laser lines or
plumb beams with a known horizontal or vertical reference
line or with already checked plumb points.
 Switch the measuring tool off during transport. When
switching off, the levelling unit, which can be damaged in
case of intense movement, is locked.
Switching On and Off
To switch on the measuring tool, slide the On/Off switch 4 to
the " on" position (when working without automatic level-
ling) or to the " on" position (when working with auto-
matic levelling). Immediately after switching on, the measur-
ing tool sends laser beams out of the exit openings 1.
 Do not point the laser beam at persons or animals and
do not look into the laser beam yourself, not even from
a large distance.
To switch off the measuring tool, slide the On/Off switch 4
to the "off" position. When switching off, the levelling unit is
locked.
Deactivating the Automatic Shut-off
When no button on the measuring tool is pressed for approx.
30 minutes, the measuring tool automatically switches off to
save the batteries.
To switch on the measuring tool after automatic shut-off, either
slide the On/Off switch 4 to the "off" position and then switch
the measuring tool on again or press the operating mode but-
ton 2 once.
To deactivate the automatic shut-off, keep the operating
mode button 2 pressed for at least 3 s (while the measuring
tool is switched on). Deactivation of the automatic shut-off is
confirmed by brief flashing of the laser beams.
 Do not leave the switched-on measuring tool unattend-
ed and switch the measuring tool off after use. Other
persons could be blinded by the laser beam.
To activate the automatic shut-off, switch the measuring tool
off and then on again.

Operating Modes

The measuring tool has several operating modes between
which you can switch at any time:
– Cross and point-line operation: The measuring tool gener-
ates a horizontal and a vertical laser line facing toward the
front as well as a vertical point beam each facing upward
and downward, and a horizontal point beam each facing
toward the front and to both sides.
– 5-point operation: The measuring tool generates a vertical
point beam each facing upward and downward, as well as
a horizontal point beam each facing toward the front and to
both sides.
– Horizontal line operation: The measuring tool generates a
horizontal laser line facing frontward.
– Vertical line operation: The measuring tool generates a ver-
tical laser line facing frontward.
All point beams run at a 90° angle to each other; the laser lines
also cross each other at a 90° angle.
Bosch Power Tools
After switching on, the measuring tool is in cross-line and
point-line operation. To change the operating mode, press
the operating mode button 2.
All operating modes can be selected both with and without

automatic levelling.

Automatic Levelling
Working with Automatic Levelling (see figures C – E)
Position the measuring tool on a level and firm support, attach
it to the holder 15 or to the tripod 16.
When working with automatic levelling, push the On/Off
switch 4 to the " on" position.
After switching on, the automatic levelling function automati-
cally compensates irregularities within the self-levelling range
of ±4°. The levelling is finished as soon as the laser points or
laser lines do not move any more.
If the automatic levelling function 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 beams flash.
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°, the laser beams light up
continuously.
In case of ground vibrations or position changes during oper-
ation, the measuring tool is automatically levelled in again. To
avoid errors by moving the measuring tool, check the position
of the laser beams with regard to the reference points upon
re-levelling.
Working without Automatic Levelling (see figure F)
For work without automatic levelling, push the On/Off switch 4
to the " on" position. When the automatic levelling is
switched off, the laser lines flash continuously.
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 beams 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
upward can divert the laser beam.
As thermal fluctuation is largest close to the ground, the meas-
uring tool, if possible, should be mounted on a commercially
available tripod 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
beginning work.
When the accuracy of the horizontal point beams is within the
maximum allowed deviation, then the accuracy of the vertical
point beams and the laser lines is thus also checked.
Should the measuring tool exceed the maximum deviation
during one of the tests, please have it repaired by a Bosch
after-sales service.
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1 609 92A 25C | (2.3.16)