H68.0.01.6C-06
Operating Manual GMK 100
page 8 of 14
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6.5 Zeroing function
It is recommended to run regularly the zeroing function
for best measuring results:
Hold the device in the air as shown in the left picture
and press key “hold” for 2 seconds.
You can easily see whether the zero point is ok with
the “rEF” characteristics. If the device shows at air a
value <0.5 or >0.5 or “Er.4” with “rEF” characteristics
you have to run the zeroing function.
Please pay attention not to influence the
zeroing function with your hands. The
best way to ensure this is shown left.
NOTE:
The zeroing function adjusts the zero-point for both 10 mm and 25 mm at the same time.
7
Wood Measuring
Choose material corresponding to your type of wood according to the table in addendum A.
Example: You want to measure Scots pine -> select material d.50
Best results are obtained if you measure
crossways to the wood’s grain. (see right picture)
Unplaned and wrinkled surfaces are causing too low measuring results!
NOTE:
Wood is a natural product. Its density fluctuates due to the tree’s
growth and flaws (knots, cracks, resin pockets, etc.). This may
lead to measuring errors up to several %u, because the
measurement depends on density.
If your kind of wood is not listed in addendum A, you have to know its
density (dry): for example a wood of density 0.68 kg/dm
3
is measured with
material d.70 (approximate actual density to the next material 0.52 ->d.50,
0.53 -> d.55).
8
Plaster Measuring
Rough surfaces will influence the measuring results. Precise values are only
obtained at even surface and without any air gap between surface and device. Metal
grids can cause additional measuring faults.
Use measuring depth “10 mm” if you want to rate plaster moisture.
There are a lot of different products for plastering with highly varying densities. This can lead to
erroneous measurements, because the measurement significantly depends on density. Please
consider the notes of chapter 11
“Measurement of Other Materials” if you rate an unfamiliar plaster.
9
Floor screed Measurement
Use measuring depth “25 mm” for floor screed measurements to rate ideally the whole thickness of
the screed.
NOTE:
Floor screed dries patchy and therefore areas may be differently wet. A big amount of
water has to be released upwards (evaporate) before you can tile it. The floor screed has
to be drier if a vapor-tight covering should be used as if it would be with a diffusion
permeable covering. Therefore the moisture rating of the device can only be a first
approximate value and the decision whether the floor is ready for further covering or not
cannot be based only on this rating.
Reinforcements (iron) or floor heating near the surface may cause erroneous measuring
results. Please consider chapter 12.2 CM-moisture.