Bosch Professional GLM 80 Manual page 15

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and grade measurement functions). For this reason, place
the measuring tool against or on a firm surface whenever
possible.
Influences on the measuring range
The measuring range depends on the lighting conditions and
the reflective properties of the target surface. For better vis-
ibility of the laser beam when working outdoors and in bright
sunlight, use the laser viewing glasses (28) (accessory) and
the laser target plate (29) (accessory) or shade the target
area.
Influences on the measurement result
Due to physical effects, the possibility of inaccurate meas-
urements when measuring various surfaces cannot be ex-
cluded. These include:
– Transparent surfaces (e.g. glass, water)
– Reflective surfaces (e.g. polished metal, glass)
– Porous surfaces (e.g. insulating materials)
– Structured surfaces (e.g. roughcast, natural stone).
If necessary, use the laser target plate (29) (accessory) on
these surfaces.
Inaccurate measurements are also possible where the laser
is pointed at target surfaces diagonally.
Layers of air at different temperatures and indirectly re-
ceived reflections can also influence the measured value.
Checking accuracy and calibrating the grade
measurement (see figure H)
Regularly check the accuracy of the grade measurement.
This is accomplished by means of a reverse measurement.
To do this, lay the measuring tool on a table and measure the
inclination. Turn the measuring tool by 180° and measure
the inclination again. The difference between the displayed
values must not exceed 0.3°.
In case of greater deviation, the measuring tool must be re-
calibrated. To do this, press and hold the grade measure-
ment button (3). Follow the directions on the display.
Accuracy check of the distance measurement
You can check the accuracy of the measuring tool as follows:
– Choose a measuring section of approx. 1–10 m in length
that is permanently unchanged, the exact length of which
is known to you (e.g. room width, door opening). The
measuring section must be indoors, and the target sur-
face of the measurement must be smooth and reflect
well.
– Measure the section ten times in succession.
The deviation between the individual measurements and the
mean value must not exceed ± 2 mm. Record the measure-
ments in order to be able to compare the accuracy later on.
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 (19)
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.
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10 20
5 25
0 30
Set the reference level for measurements with a tripod by
pressing the button (10) accordingly (thread reference
level).
Working with the measuring rail (see figures I–K)
The measuring rail (25) can be used for a more exact grade
measurement result. Distance measurements are not pos-
sible with the measuring rail.
Insert the measuring tool into the measuring
rail (25) as shown and lock the measuring tool
in place with the locking lever (26). Press the
measuring button (2) to activate the "measur-
ing rail" operating mode.
Regularly check the accuracy of the grade measurement by
means of a reverse measurement or the levels on the meas-
uring rail.
In case of greater deviation, the measuring tool must be re-
calibrated. To do this, press and hold the grade measure-
ment button (3). Follow the directions on the display.
To end the "measuring rail" operating mode, switch off the
measuring tool and remove it from the measuring rail.
Errors – Causes and Corrective Measures
Cause Corrective measures
Temperature warning(j) flashes, measurement not pos-
sible.
The measuring tool is outside Wait until the measuring tool
the operating temperature of has reached operating tem-
–10 °C to +50 °C (in the con- perature.
tinuous measurement func-
tion, up to +40 °C).
Display shows "ERROR"
Addition/subtraction of Only add/subtract measured
measured values with differ- values with the same units of
ent units of measurement. measurement.
Angle between laser beam Increase the angle between
and target is too acute. the laser beam and the target
Target surface is too reflect- Use the laser target plate
ive (e.g. mirror) or not re- (29).
flective enough (e.g. black
material), or ambient light is
too bright.
The laser beam output (16) Wipe the laser beam output
and/or reception lens (17) (16) and/or reception lens
(17) dry with a soft cloth.
are fogged up (e.g. due to a
rapid temperature change).
Calculated value is larger Divide the calculation into in-
2 3
than 999,999 m/m /m . termediate steps.
Display shows "> 60°" or "< –60°"
The grade measuring range Perform the measurements
for the measuring function or within the specified angle
reference level has been ex- range.
ceeded.
Display shows "CAL" and "ERROR"
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