Page 66 - Lehrbuch Neigungsmessung deutsch 2018.indd

COMPENDIUM INCLINATION MEASUREMENT
WYLER AG, WINTERTHUR / SWITZERLAND

6.4 WHAT NEEDS SPECIAL ATTENTION WHEN MEASURING?

• Influence of temperature:
A temperature difference of 1 degree Celsius between the upper and the lower side of a plate of
1m length already results in a deformation of the plate of 6 to 7 μm.
• Choice of measuring base:
For the measurement of a surface:
Ideal measuring base: Flat steel base with dust grooves
• Measuring step length:
Length of the base Optimal step length Recommended step length
110 mm 90 mm 85 ... 105 mm
150 mm 126 mm 120 ... 145 mm
200 mm 170 mm 160 ... 190 mm
SPECIAL BASE (Flexbase)
6.4.1 THE TERMS ARE EXPLAINED IN MORE DETAIL WITH THE AID OF A
LINE MEASUREMENT BY HAND
A measuring bar 1080 mm in length is to be
measured for straightness. The BlueLEVEL has
a base length of 200 mm. According to the abo-
ve list, a step length of 180 mm has been cho-
sen. The chosen step length will be marked on
the measuring bar with a fine line.

For the measurement it is now important that
• the temperature of the object and the ins-
trument are identical
• the individual measurements are overlap-
ping, which means that the beginning of
a measurement is always the same as the
end point of the previous measurement
• the measuring instrument has to be mo-
ved in the direction of the cable connector
• you wait for about 5 to 8 seconds after
Maximum error (straightness) = moving the instrument to stabilize the
15.5 μm x 180 mm = 2.79 μm sensor of the instrument
1000 mm

The thus measured values are marked in a corresponding graph and the individual measuring points
have to be connected to each other. We then connect the two end points (in our example starting point (0)
and last measuring point (+7)) with a straight line. Parallel to this line, we draw an additional line on each
side through the most distant points. The vertical distance between these parallels corresponds with the
straightness of the measured line, resp. of the measured setting straight edge. In our example, these are
supposedly 15.5 μm. Why supposedly?
For simplicity, we have taken over the readings of the display from the BlueLEVEL into the graph. The
unit of the value displayed on the instrument is x μm/m. In fact, we would have to reduce each measured
point to the step length of 180 mm. We now obtain this, by converting the intermediate result of 15.5 μm
to 180 mm and thus obtain an effective straightness of 2.79 μm. When measuring the straightness with the
software, this is not an issue since the measured values are directly converted to the step length.
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