Bosch GLM 50 C Professional Original Instructions Manual page 42

OBJ_BUCH-2450-006.book Page 42 Monday, December 18, 2017 12:17 PM
42 | English
laser viewing glasses 18 (accessories) and the laser target plate 17 (accessories) or
shade the target area.
Influence Effects on the Measuring Result
Due to physical effects, faulty measurements cannot be excluded when measuring on
different surfaces. Included here are:
– Transparent surfaces (e.g., glass, water),
– Reflecting surfaces (e.g., polished metal, glass),
– Porous surfaces (e.g. insulation materials),
– Structured surfaces (e.g., roughcast, natural stone).
If required, use the laser target plate 17 (accessory) on these surfaces.
Furthermore, faulty measurements are also possible when sighting inclined target
surfaces.
Also, air layers with varying temperatures or indirectly received reflections can affect
the measured value.
Accuracy Check and Calibration of the Grade Measurement (Tilt Calibration)
(see figure G)
Regularly check the accuracy of the grade measurement. This is done by carrying out
a reversal measurement. For this, place the measuring tool on a table and measure
the grade. Turn the measuring tool by 180 ° and measure the grade again. The differ-
ence of the indicated reading may not exceed by more than 0.3 ° (max.).
In the event of larger deviations, you have to recalibrate the measuring tool. For this,
select . Follow the instructions on the display.
CAL
After severe temperature changes and impact, we recommend an accuracy check
and, if required, to recalibrate the measuring tool. After a temperature change, the
measuring tool must acclimate for a while before calibrating.
Accuracy Check of the Distance Measurement
The accuracy of the measuring tool can be checked as follows:
– Select a permanently unchangeable measuring section with a length of approx. 3
to 10 metres; its length must be precisely known (e.g. the width of a room or a door
opening). The measurement should be carried out under favourable conditions,
meaning, the measuring distance must be indoors and the target surface for the
measurement must be smooth and reflect well.
– Measure the distance 10 times in succession.
The deviation of the individual measurements from the average value must not exceed
±4 mm over the entire measuring section in favourable conditions. Record the meas-
urements in order to be able to compare the accuracy at a later date.
1 609 92A 48U | (18.12.17) Bosch Power Tools