Bosch Professional GRL 350 HV Instructions Manual page 14

14 | English
Accuracy Check of the Measuring Tool
The following tasks should be performed only by well-trained
and qualified persons. The legalities with regard to perform-
ing an accuracy check or calibration of a measuring tool must
be known.
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.
If the measuring tool exceeds the maximum deviation for the
measuring procedures described below, perform a calibra-
tion (see "Calibrating the measuring tool", page 14) or have
the measuring tool checked by a Bosch customer service
agent.
Checking the levelling accuracy in a horizontal position
For a reliable and precise result, it is recommended that you
check there is a free measuring distance of 30 m on firm
ground in front of a wall. Carry out a complete measuring
procedure for each of the two axes.
– Mount the measuring tool in a horizontal position 30 m
from the wall on a tripod, or place it on a firm, level sur-
face. Switch on the measuring tool.
30 m
– Once levelling is complete, mark the centre of the laser
beam on the wall (point Ⅰ).
d
– Rotate the measuring tool 180° without changing its posi-
tion. Allow it to level in and mark the centre point of the
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laser beam on the wall (point Ⅱ). Note that point Ⅱ should
preferably be positioned vertically above or below point Ⅰ.
The discrepancy d between the two marked points Ⅰ and Ⅱ
on the wall reveals the actual height deviation of the measur-
ing tool for the axis being measured.
Repeat the measuring process for the other axis. To do this,
turn the measuring tool by 90° before beginning the meas-
urement.
The maximum permitted deviation on the 30 m measuring
distance is as follows:
30 m × ±0.05 mm/m = ±1.5 mm. The discrepancy d
between points Ⅰ and Ⅱ must therefore amount to no more
than 3 mm for each of the two measuring processes.
Calibrating the measuring tool
The following tasks should be performed only by well-trained
and qualified persons. The legalities with regard to perform-
ing an accuracy check or calibration of a measuring tool must
be known.
Perform calibration of the measuring tool with ex-
u
treme precision or have the measuring tool checked
by a Bosch customer service agent. Inaccurate calibra-
tion leads to incorrect measuring results.
Only start the calibration if you have to perform a cal-
u
ibration of the measuring tool. As soon as the measur-
ing tool is in calibration mode, you must perform the cal-
ibration meticulously to the end in order to ensure that no
incorrect measuring results are produced afterwards.
Check the levelling accuracy after every calibration (see
"Accuracy Check of the Measuring Tool", page 14). If the
deviation is outside the maximum permitted limits, have the
measuring tool checked by a Bosch customer service agent.
Always calibrate all axes (X-axis, Y-axis and Z-axis).
Note: If the X-axis (7) or Y-axis (6) status indicator flashes
red during calibration, this indicates that the deviation is
outside the maximum permitted range. If this is the case,
press the manual operation button (14) to exit calibration
mode without saving the settings. The X-axis (7) and Y-
axis (6) status indicators will ten flash red at 3×/s to indicate
calibration errors.
Restart the calibration. If the error occurs again, have the
measuring tool checked by a Bosch customer service agent.
X-axis and Y-axis Calibration
For calibration, you will need a free measuring distance
of 30 m on firm ground in front of a wall.
If required (e.g. in poor lighting conditions), you can use a
180°
laser receiver (37) to mark the laser beam. When using the
laser receiver, take care that it is aligned vertically on the
wall, as otherwise the marks are offset with respect to the
laser beam. With laser receivers with an adjustable recep-
tion accuracy, you can set the reception accuracy depending
on the required calibration accuracy (see the operating in-
structions for the laser receiver).
Mounting and aligning the measuring tool for calibration:
Mount the measuring tool in the horizontal position 30 m
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