Accuracy Check Of The Measuring Tool - Bosch GPL 5 Professional Manual Original

After switching on, the automatic levelling function automat-
ically compensates irregularities within the self-levelling
range from ±5° (longitudinal axis) and ±3° (lateral axis). 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 sur-
face on which the measuring tool stands deviates by more
than 5°/3° from the horizontal plane, the laser beams will
flash quickly.
If this is the case, set up the measuring tool in a level position
and wait for the self-levelling to take place. As soon as the
measuring tool is within the self-levelling range of ±5/±3°,
the laser beams will light up continuously.
In case of ground vibrations or position changes during oper-
ation, the measuring tool is automatically levelled again.
After each levelling process, check the position of the hori-
zontal and/or vertical laser beams in relation to the refer-
ence points to avoid errors arising from a change in the
measuring tool's position.

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.
Since the temperature stratification is greatest at ground
level, you should always mount the measuring tool on a tri-
pod for measuring distances of 20 m or more. In addition,
position the measuring 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.
When the levelling accuracy of the horizontal laser beams for
the longitudinal and lateral axis is within the maximum allow-
able deviation, then the levelling accuracy for the plumb
beams (vertical axis) 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.
Checking the horizontal levelling accuracy of the
longitudinal axis
For this check, you will need a free measuring distance of
20 m on firm ground between two walls (designated A
and B).
– Mount the measuring tool close to wall A on the holder or
a tripod, or place it on a firm, level surface. Switch on the
measuring tool.
Bosch Power Tools
A
20 m
– Aim the horizontal laser beam that runs parallel to the lon-
gitudinal axis of the measuring tool at the closer wall A
and allow the measuring tool to level in. Mark the centre
of the laser point on the wall (point Ⅰ).
A
180°
– Turn the measuring tool 180°, allow it to level in and mark
the centre point of the laser beam on the opposite wall B
(point Ⅱ).
– Position the measuring tool – without rotating it – close to
wall B, switch it on and allow it to level in.
A
– Align the height of the measuring tool (using the tripod or
by placing objects underneath as required) so that the
centre point of the laser beam exactly hits the previously
marked point Ⅱ on wall B.
A
d
English | 11
B
B
B
B
180°
1 609 92A 4HT | (29.01.2019)