Working Advice - Bosch GRL 250 HV Professional Originalbetriebsanleitung

The deviations have an impact on measuring distances of ap-
prox. 20 m or more, and at 100 m the deviation can easily
be two to four times larger than that at 20 m.
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.
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
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 through 90° before beginning the
measurement.
The maximum permitted deviation on the 30 m measuring
distance is as follows:
30 m × ±0.1 mm/m = ±3 mm. The discrepancy d between
points Ⅰ and Ⅱ must therefore amount to no more than 6 mm
for each of the two measuring processes.
Bosch Power Tools

Working Advice

Only the centre of the laser point or laser line must be
u
used for marking. The size of the laser point/the width of
the laser line changes depending on the distance.
Working with the Laser Target Plate (see figure C)
The laser target plate (47) improves visibility of the laser
beam in unfavourable conditions and at greater distances.
The reflective surface of the laser target plate (47) improves
visibility of the laser line. The transparent surface enables
the laser line to be seen from behind the laser target plate.
Working with the Tripod (Accessory)
A tripod offers a stable, height-adjustable support surface
for measuring. Place the measuring tool with the 5/8" tripod
mount (21) on the thread of the tripod (38). Tighten the
measuring tool using the locking screw of the tripod.
On a tripod featuring a measuring scale on its extender, you
can set the height deviation straight away.
Roughly align the tripod before switching on the measuring
tool.
Working with the WM 4 wall mount (accessory)
(see figure D)
You can also mount the measuring tool on the wall mount
with the alignment unit (42). For this, screw the 5/8"
screw (44) of the wall mount into the tripod mount (21) of
the measuring tool.
Mounting on a wall: Wall-mounting is advisable, for ex-
ample for work performed above the maximum extension
height of tripods, or for work on unstable surfaces and
without tripods.
Fasten the wall mount (42) either to a wall using screws
through the fixing holes (40) or to a strip of wall using the
fastening screw (39). Fit the wall mount as perpendicular as
180°
possible to the wall and ensure it is mounted in a stable way.
Mounting on a tripod: You can also screw the wall
mount (42) on to a tripod (41) using the tripod mount on
the back. This type of mount is particularly suited to work
where the rotation level is supposed to be aligned to a refer-
ence line.
You can use the alignment unit to slide the measuring tool
vertically (if mounted on the wall) or horizontally (if mounted
on a tripod) up to approx. 16 cm. To do this, loosen the
bolt (43) on the alignment unit, slide the measuring tool into
the required position, and retighten the bolt (43).
Working with the Laser Receiver (accessory)
Use the laser receiver (36) to improve detection of the laser
lines in adverse lighting conditions (bright environment, dir-
ect sunlight) and over greater distances.
For rotary lasers with multiple operating modes, select the
horizontal or vertical operation with the highest rotational
speed.
Before working with the laser receiver, read and observe the
laser receiver operating instructions.
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1 609 92A 5S1 | (09.09.2020)