H60.0.13.6C-17 Operating Manual GMH 3851 Page 10 of 22
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5.8 Measuring other materials
5.8.1 ‘Hard‘ materials (concrete or similar): Measuring with brush-type probes (GBSL91 or GBSK91)
Drill two holes with Ø6mm (GBSK91) or Ø 8mm (GBSL91) at intervals of 8
to 10cm into the material to be measured. Do not use edgeless drills: the
resulting heat will evaporate the moisture which will result in faulty
measures. Wait for at least 10min, blow out the holes to clean them from
dust. Apply conductivity compound on the brush-type probes and stick
them into the holes. Choose correct material (see Appendix B: Additional
materials), read the measuring value. Observe that the holes dry out by-
and-by, and the device will measure a value too low, if you want to use
them several times.
This effect can be compensated by using conductivity compound: insert
profuse conductivity compound between the holes and the brush-type
probe, and let the electrode stick in the hole for about 30min before
measuring (with the device switched off ). Temperature-compensation
plays no role when using the building material measuring.
Measuring with brush probe GBSL91
5.8.2 ‘Soft‘ Materials (polystyrene or similar): Measuring with measuring-rods or -pins (GMS 300/91)
Useable electrodes: impact electrode GSE91 or GSG91, reciprocating piston electrode GHE91.
Procedure as described in chapter measuring in wood.
5.8.3 Measuring bulk cargo, bales and other special measures
Usable probes e.g. injection probe GSF 40, GSF 50 (GSF 38) or measuring rods GMS 300/91 mounted on
GSE91 or GSG91.
Measuring of splints, wood chips, insulating material and similar – GSF 40 / GSF 50:
When using injection probes or measuring pins oscillating movements have to be avoided when pushing in the
probes. Otherwise hollows between the probes and the material may falsify the measuring. The material should
be sufficiently compressed. When in doubt repeat the measuring a few times: the highest measuring value is the
most exact one. Especially when using the injection probe pay attention having a foulness-free plastic insulator
(situated immediately underneath the measuring-needle).
Measuring bale of straw and hay bale – GSF 40 (GSF 38/50): Always inject the electrodes form the plain side
of the bale, never from the round side, the probe can be inserted much more slightly, esp. when using GSF 38/50.
5.9 Measuring of materials, having no characteristic curves stored
Choose the representative universal material group “h.A“, “h.b“, “h.c“ and “h.d“(for example corresponding to
A,B,C and D of the GHH91) if a conversion table exists.
Attention: The moisture evaluation wet/dry of these material groups is only valid for wood!
Please keep in mind the following when using the temperature-compensation:
Automatic temperature-compensation should always be activated when measuring wood (Act on), with all
other materials the automatic temperature-compensation should be switched off (Act off) and a manual
temperature of 20°C should be entered.
Additionally at GMH3851: The GMH3851 can store up to 4 additional user characteristic curves. For this
the corresponding reference point measurements for the respective material has to be carried out, from
which the exact moisture content has to be dedicated with the Darr-Probe or the CM-Method. The Results
can be stored in the device with the help of the GMHKonfig-Software, and can be accessed by the device
directly.
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