Bosch GLM 120 C Professional Original Instructions Manual Download

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| English

1 609 92A 4F4 | (22.10.2018)

Bosch Power Tools

Checking accuracy and calibrating the target
indicator (crosshairs)

Check the accuracy of the alignment of the laser and target
indicator on a regular basis.
– Select a bright area at least five metres away with as little

illumination as possible (e.g. a white wall) as the target.

– Check whether the laser point is inside the target indic-

ator in the display.

If the laser point is not inside the target indicator, you must
recalibrate the target indicator.
To do so, select in the settings. Follow the directions on
the display.

Working with the tripod (accessory)

The use of a tripod is particularly necessary for larger dis-
tances. Place the measuring tool with the 1/4" thread

(17)

on the quick-release plate of the tripod

(27)

or a conven-

tional camera tripod. Tighten it using the locking screw of the
quick-release plate.
Set the reference level for measurements with a tripod in the
settings (tripod reference level).

Errors – Causes and Corrective
Measures

Cause

Corrective measures

Temperature warning flashes, measurement not pos-
sible

The measuring tool is outside
the operating temperature of
–10 °C to +45 °C (in the con-
tinuous measurement func-
tion, up to +40 °C).

Wait until the measuring tool
has reached operating tem-
perature.

Display shows "ERROR"

Addition/subtraction of
measured values with vari-
ous units of measurement.

Only add/subtract measured
values with the same units of
measurement.

Angle between laser beam
and target is too acute.

Increase the angle between
the laser beam and the tar-
get.

Target surface is too reflect-
ive (e.g. mirror) or not re-
flective enough (e.g. black
material), or ambient light is
too bright.

Use the laser target plate

(25)

The laser beam output

(18)

reception lens

(20)

or cam-

era

(19)

are fogged up (e.g.

due to a rapid temperature
change).

Wipe the laser beam output

(18)

, reception lens

(20)

camera

(19)

dry with a soft

cloth.

Calculated value is larger
than +1,999,999 or smaller
than -999,999 m

Divide the calculation into in-
termediate steps.

Cause

Corrective measures

Display shows "CAL" and "ERROR"

The calibration of the grade
measurement has not been
carried out in the right order
or has not been carried out in
the correct positions.

Repeat the calibration ac-
cording to the instructions
that appear on the display
and in the manual.

The surfaces used for calib-
ration were not precisely ho-
rizontal or vertical.

Repeat the calibration on a
horizontal or vertical surface
and check the surfaces be-
forehand if necessary using a
spirit level.

The measuring tool has
moved or tilted when the
button was pressed.

Repeat the calibration and
hold the measuring tool still
against the surface when
pressing the button.

Battery charge indicator (g), temperature warning and
"ERROR" shown in the display

The temperature of the
measuring tool is outside the
permissible charging temper-
ature range.

Wait until the charging tem-
perature range has been
reached.

Battery charge indicator (g) and "ERROR" shown in the
display

The battery charging voltage
is not correct.

Check whether the connec-
tion has been established
correctly and that the char-
ger is working properly. If the
device symbol flashes, the
battery is defective and must
be replaced by the Bosch
after-sales service.

Measurement result implausible

Target surface reflection not
distinct (e.g. water, glass).

Cover the target surface.

The laser beam output

(18)

reception lens

(20)

or cam-

era

(19)

is covered.

Keep the laser beam output