GHM-Messtechnik GMH 3851 ab User manual

H60.0.13.6C-17
GHM Messtechnik GmbH - Standort Greisinger
Hans-Sachs-Str. 26 - 93128 Regenstauf GERMANY
+49 9402 / 9383-0 +49 9402 / 9383-33 [e-mail]
Operating Manual
Resistive Moisture And Temperature Measuring Instrument
With Data Logger And Programmable User Curves
ab Version 2.2
GMH 3851

Please carefully read these
instructions before use!
WEEE-Reg.-Nr. DE 93889386

Please consider the safety instructions!

Please keep for future reference!

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Index
1GENERAL NOTE......................................................................................................................................................3
2SAFETY......................................................................................................................................................................3
2.1 INTENDED USE.......................................................................................................................................................3
2.2 SAFETY SIGNS AND SYMBOLS................................................................................................................................3
2.3 SAFETY INSTRUCTIONS .........................................................................................................................................3
3PRODUCT DESCRIPTION......................................................................................................................................4
3.1 SCOPE OF SUPPLY ..................................................................................................................................................4
3.2 OPERATING AND MAINTENANCE...........................................................................................................................4
3.3 START UP AND READINESS FOR OPERATION..........................................................................................................4
3.4 CONNECTIONS .......................................................................................................................................................5
3.5 DISPLAY ELEMENTS ..............................................................................................................................................5
3.6 KEYPAD.................................................................................................................................................................5
4DEVICE CONFIGURATION...................................................................................................................................6
5SOME BASICS OF PRECISION MATERIAL MOISTURE MEASURING......................................................7
5.1 MEASURING METHOD ...........................................................................................................................................7
5.2 MOISTURE CONTENT UAND WET-BASIS MOISTURE CONTENT W........................................................................7
5.3 SPECIAL FEATURES OF THE DEVICE.......................................................................................................................7
5.4 AUTO-HOLD FUNCTION.........................................................................................................................................7
5.5 AUTOMATIC TEMPERATURE-COMPENSATION ('ATC') ...........................................................................................7
5.6 MEASURING IN WOOD:MEASURING WITH TWO MEASURING-NEEDLES.............................................................8
5.7 SPLIT LOG FIREWOOD MEASURING........................................................................................................................8
5.7.1 Presetting.......................................................................................................................................................8
5.7.2 Sampling ........................................................................................................................................................8
5.7.3 Measuring......................................................................................................................................................9
5.8 MEASURING OTHER MATERIALS ........................................................................................................................10
5.8.1 ‘Hard‘ Materials (concrete or similar): Measuring with brush-type probes (GBSL91 or GBSK91)............10
5.8.2 ‘Soft‘ Materials (polystyrene or similar): Measuring with Measuring-rods or -pins (GMS 300/91)...........10
5.8.3 Measuring bulk cargo, bales and other special measures...........................................................................10
5.9 MEASURING OF MATERIALS,HAVING NO CHARACTERISTIC CURVES STORED ....................................................10
6HINTS FOR SPECIAL FUNCTIONS ...................................................................................................................11
6.1 MOISTURE EVALUATION ('WET' -'MEDIUM' -'DRY')...................................................................................11
6.2 PRE-SELECTION OF FAVOURITE MATERIALS ('SORT')..........................................................................................11
6.3 INDIVIDUALLY PROGRAMMABLE CHARACTERISTIC CURVES.............................................................................11
7OPERATION OF LOGGER...................................................................................................................................12
7.1 “FUNC-STOR“: STORING SINGLE MEASUREMENTS.............................................................................................12
7.2 “FUNC-CYCL“: AUTOMATIC RECORDING WITH SELECTABLE LOGGER-CYCLE-TIME .....................................13
8OUTPUT ...................................................................................................................................................................14
8.1 INTERFACE -BASE ADDRESS ('ADR.') .................................................................................................................14
8.2 ANALOGUE OUTPUT –SCALING WITH DAC.0 AND DAC.1................................................................................14
9APPLICATION IN THE GLUED TIMBER CONSTRUCTION AND LAMINATED TIMBER PRODUCTION.............................14
10 FAULT AND SYSTEM MESSAGES.....................................................................................................................15
11 INSPECTION OF THE ACCURACY / ADJUSTMENT SERVICES................................................................15
12 RESHIPMENT AND DISPOSAL...........................................................................................................................15
13 SPECIFICATION....................................................................................................................................................16
14 APPENDIX A: SORTS OF WOOD .......................................................................................................................17
15 APPENDIX B: ADDITIONAL MATERIALS ......................................................................................................22
15.1 MEASURING OF BUILDING MATERIALS ............................................................................................................22
15.2 MEASURING OF AGRICULTURAL BULK CARGO................................................................................................22
15.3 ESTIMATION OF ADDITIONAL MATERIALS .......................................................................................................22

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1 General note
Read through this document attentively and make yourself familiar to the operation of the device before you
use it. Keep this document in a ready-to-hand way in order to be able to look up in the case of doubt.
2 Safety
2.1 Intended use
The device is suitable for the measurement of moisture content and temperature.
The measurement is done using appropriate electrodes and cables. The electrodes are connected via a BNC
(moisture) or thermocouple connector (temperature).
It is designed for the mobile use or the stationary operation in a controlled electromagnetic environment (lab).
The electrodes are connected via 7-pole bayonet connection.
Personnel which starts up, operates and maintains the device has to have sufficient knowledge of the
measuring procedure and the meaning of the resulting measured values, this manual delivers a valuable
help for this. The instructions of the manual have to be understood, regarded and followed.
To be sure that there´s no risk arising due to misinterpretation of measured values, the operator must have
further knowledge in case of doubt - the user is liable for any harm/damage resulting from misinterpretation
due to insufficient knowledge.
The manufacturer will assume no liability or warranty in case of usage for other purpose than the intended
one, ignoring this manual, operating by unqualified staff as well as unauthorized modifications to the device.
2.2 Safety signs and symbols
Warning notices are marked in this manual as shown below:
Caution! This symbol warns of imminent danger, death, serious injuries and significant
damage to property at non-observance.
Attention! This symbol warns of possible dangers or dangerous situations which can
provoke damage to the device or environment at non-observance.
Note! This symbol point out processes which can indirectly influence operation, possibly
cause incorrect measurement or provoke unforeseen reactions at non-observance.
2.3 Safety instructions
This device has been designed and tested in accordance to the safety regulations for electronic devices.
However, its trouble-free operation and reliability cannot be guaranteed unless the standard safety measures
and special safety advises given in this manual will be adhered to when using it.
1.
Trouble-free operation and reliability of the device can only be guaranteed if it is not subjected to any
other climatic conditions than those stated under “Specification”.
Transporting the device from a cold to a warm environment condensation may result in a failure of the
function. In such a case make sure the device temperature has adjusted to the ambient temperature
before trying a new start-up.
2.
Whenever there may be a risk whatsoever involved in running it, the device has to be
switched off immediately and to be marked accordingly to avoid re-starting. Operator
safety may be a risk if:
- there is visible damage to the device
- the device is not working as specified
- the device has been stored under unsuitable conditions for a longer time
In case of doubt, please return device to manufacturer for repair or maintenance.

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3.
Do not use this product as safety or emergency stop device or in any other application
where failure of the product could result in personal injury or material damage.
Failure to comply with these instructions could result in death or serious injury and
material damage.
4.
This device must not be used at potentially explosive areas! The usage of this device at
potentially explosive areas increases danger of deflagration, explosion or fire due to
sparking.
5.
Risk of injury due to sharp measuring needles depending on the used electrode! Please
protect needles while not used with suitable means of protection.
3 Product description
3.1 Scope of supply
Handheld instrument
9V battery
Operating Manual
3.2 Operating and maintenance
1. Battery Operation
The battery has been used up and needs to be replaced, if ´bAt´ is shown in lower display. The device
will, however, continue operating correctly for a certain time.
The battery has been completely used up, if ´bAt´ is shown in the upper display.
2. The battery has to be removed, when storing device above 50°C.
We recommend to remove the battery if device is not used for a longer period of time!
Risk of leakage!
3. Treat device and probes carefully. Use only in accordance with above specification. (do not throw, hit
against etc.). Protect plugs and sockets from soiling.
4. Mains Operation
When using a power supply unit please note that operating voltage has to be 10.5 to 12 V
DC. Do not apply over voltage!! Simple 12V-power supplies often have excessive no-load
voltage. We, therefore, recommend using regulated voltage power supplies. Trouble-free
operation is guaranteed by our power supply GNG10/3000.
Prior to connecting the plug power supply with the mains supply make sure that the operating voltage
stated at the power supply is identical to the mains voltage.
5. Cable break or no connected / too dry / highly insulating material:
There may still corresponding %-values are displayed
- This shall not constitute a valid test result!
6. Maintenance: The device does not contain serviceable parts inside.
Regular inspection of contacts and cable is suggested, the precision of the measuring chain can be
checked with the optional testing adapter GPAD 38
The measuring needles have to be fixed very well e.g. by means of a wrench. Loose needles can disturb
the measuring.
3.3 Start up and readiness for operation
After switching on the instrument, a self test is performed (approximately 5 seconds).
During this time all display segments are shown.
After this sequence the instrument changes to measuring operation and is ready for use.

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3.4 Connections
1:
Output:
Operation as interface: Connect to optically isolated interface
adapter (accessory: GRS 3100 or USB 3100 N)
Operation as analogue output: Connection via suitable cable.
Attention: The output mode has to be configured (p.r.t chapter 8)
and influences battery life!
2:
Sensor-connection: BNC
3:
Temperature-probe-connection: Thermocouple type K (NiCr-
Ni) for temperature-compensation with an external temperature-
probe
4:
The mains socket is located at the left side of the instrument.
3.5 Display elements
1:
Main display: Currently measured material moisture
[percent moisture content]
HLD: Measure value is ‘frozen‘ (key 6)
2:
Auxiliary display: Currently selected material (temperature
when pressing key 3) Blinking display: Displayed value is out of
specified range (wood 8..40 %u)
Special display elements:
3:
Moisture evaluation: Evaluation of the material condition: via
top arrows: DRY - MEDIUM - WET
4:
Warning triangle: Indicates low battery
5:
“%u” or “%w”:Displays unit: moisture content u or wet basis
moisture content w
6:
T external-arrow: Appears if an external temperature-probe is
connected and automatic temperature compensation is activated.
7:
Logg-arrow: Shown if logger function is selected,
flashes if cyclic logger is running
All remaining arrows have no function in this version.
3.6 Keypad
1:
On/Off key
3:
During measurement: shortly displaying temperature
or changing to temperature input.
4:
Set/Menu: press (Menu) for 2 s: configuration will
activated
2 and 5:
During measurement: select a material
p.r.t.: 6.2 Pre-selection of favourite materials ('Sort')
List of selectable materials:
Appendix A; Appendix B
With manual temperature compensation:
When displaying temperature (call via button ‚Temp‘): Input of temperature
up/down for configuration:
to enter values or change settings
6:
During Measurement:
-with Auto-Hold off: Hold current measuring value ('HLD' in display)
-with Auto-Hold on: Start a new measure, which is ready when 'HLD' appears in
the display. refer to chapter 5.4 Auto-Hold function
-or calling of the logger functions (refer to chapter 7)
Set/Menu or temperature input:
confirming of selected input, return to measure

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4 Device configuration
Some menu items will be shown depending on the actual device configuration (e.g. there are
some items disabled when the logger contains data). Please note the hints by the menu items.
For configuration of the device press "Menu"-key (key 4) for 2 seconds, the main menu will be shown (main display:
“SEt”). Choose the desired menu branch by pressing the "Menu"-key (key 4). By pressing “” (key 3) the referring
parameters can be chosen. The referring values are changed by pressing the keys "" (key 2) or "" (key 5) (Choice
of parameter: “”). Pressing “Menu” (key 4) again will jump back to the main menu selection and stores the settings.
Use key "Store/" (key 6) to leave configuration..
Menu
Parameter
Values
Meaning

or
p.r.t.
Set Sort
Set sort: limitation of the material selection
oFF
Unrestricted material selection via key 2 and 5
*
1...8:
Material selection in-between 1 up to 8 selectable materials
...
selectable materials (not available if Sort = off). Select the desired
material that should be available during the measure via key 2 and 5.
*
Set
Conf
Set configuration: Generic settings
Arrow bottom left
points to “%u”
Moisture display = moisture content [%u]
*
Arrow bottom left
points to “%w”
Moisture display = wet-basis moisture content [%u]
°C
All temperature values are in degrees Celsius
°F
All temperature values are in degrees Fahrenheit
oFF
Atc off: temperature input for compensation via keys
*
*
5.4
on
Atc on: temperature compensation via internally measured temperature
or external probe
oFF
Auto HLD off: continuous measuring.
*
5.4
on
Auto-HLD on: when reaching a stable measuring result, this will be
frozen with-HLD. When pressing the store-key a new measure will be
initiated. If logger is switched on (‚Func CYCL‘, ‚Func Stor‘): device
works like setting would be “auto-HLD off”
oFF
Average value calculation off
5.6
on
Average value calculation on: Average value out of 3 sequential
measuring is calculated and displayed
1...120
Power-off delay in minutes.
Device will be automatically switched off as soon as this time has
elapsed if no key is pressed/no interface communication takes place
oFF
Power-off function inactive (continuous operation, e.g. mains operation)
oFF
Function of the output: No output function, lowest power consumption
8
SEr
Output is serial interface
dAC
Output is analogue output 0...1V
01, 11 .. 91
Base Address when Output = Serial Interface :
Base address of device for interface communication.
0
0.0 ... 100.0%
Enter desired moisture value at which the analogue output potential
should be 0V
8.2
0.0 ... 100.0%
Enter desired moisture value at which the analogue output potential
should be 1V
8.2
Set Logg
Set logger: Configuration of logger function
CYCL
Cyclic: logger function ‚cyclic logger‘
*
7
Stor
Store: logger function ‚individual value logger‘
oFF
no logger function
0:30 ... 60:00
Cycle time of cyclic logger [minutes:seconds]
*
7.2
Set CLOC
Set clock: Setting of real time clock
HH:MM
Clock: Setting of time hours:minutes
YYYY
Year
DD.MM
Date: day.month
The settings will be set to the settings ex works, if keys ‘Set‘ and ‘Store‘ are pressed
simultaneously for more than 2 seconds.
(*) If the logger memory contains data already, the menus/parameters marked can not be called!
If these should be altered the logger memory has to be cleared before!
If the manual logger contains data (Logger: ‘Func Stor’), the first menu displayed will be: ‘rEAd Logg’
please refer to chapter 7.1

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5 Some basics of precision material moisture measuring
5.1 Measuring method
The electrical resistance depends on the material moisture in many cases. Therefore the device measures the (possibly
extremely high) values of resistance and converts them to the displayed value by means of integrated characteristic
curves. The temperature has to be compensated especially at the measurement of wood –please refer to chapter 5.5.
The contact is realised e.g. by nails that are driven into the material or by injection probes.
Frozen material cannot be measured!
5.2 Moisture content uand wet-basis moisture content w
Depending on the Application one of the two units is necessary.
Carpenters, joiners and the like commonly use the moisture content u (sometimes referred to as MC).
When evaluating firewood, wood chips etc., the wet basis moisture content w is needed.
The instrument can be configured to both of the values. Please refer to chapter “configuration“.
Moisture content u or MC (relative to dry weight) = dry basis moisture content (mind the arrow at left bottom!)
The unit is %, sometimes used: % MC.
The unit expresses the moisture content like calculated below:
Moisture content u [%] = (weightwet - weightdry) / weightdry *100
Or: Moisture content u [%] = (weightwater) / (weightdry) *100
weightwet: weight of the wet material
weightwater: weight of water in the wet material
weightdry: oven-dry weight of material
Example: 1kg of wet wood, which contains 500g of water has a moisture content u of 100%
Wet-Basis Moisture Content w (relative to total weight, mind the arrow at left bottom!)
The wet-basis moisture content expresses the ratio of the mass of water to the total mass of the substance. The ratio is
represented by the following equation (the unit is % as well):
wet-basis moisture w[%] = (weightwet - weightdry) / weightwet *100
Or: wet-basis moisture w[%] = (weightwater) / weightwet *100
Example: 1kg of wet wood, which contains 500g of water has a moisture content u of 50%
5.3 Special features of the device
466 wood specimens and 28 building materials are stored directly in the memory of the device:
Thus more exact measurements could be reached than with common devices with group selections would ever reach.
Even the usage of complex conversion tables for building materials won’t be necessary any more!
Example: Common wood-moisture-measuring-devices use one single group for spruce and oak, in reality the deviation
of these characteristic curves is more than 3%! (Base for this statement are complex statistical surveys, considered
measuring range 7-25%). This random error will not occur for the whole GMH38xx series, with the help of individual
characteristic curves highest resolution is achieved.
Extreme wide measuring range: 0-100% (depending on characteristic curve) percent moisture content in wood.
Moisture evaluation: Additionally to the measuring value, an individual moisture evaluation will be displayed
simultaneously.
5.4 Auto-Hold function
Particularly when measuring dry wood, electrostatic charges and other similar noise could dither the measuring value.
With activated auto-hold function the device will acquire an exact measuring value automatically. During that, the device
could be put down to avoid noise through discharge of the clothing etc. After having acquired the measuring value, the
display will change to ‘HLD’: The value will be frozen as long as a new measuring is initiated by pressing key 6 (store).
If the logger is switched on (‘Func CYCL’ or ‘Func Stor’), the auto-hold function can not be used. The device
works like it is set to Auto-HLD = off.
5.5 Automatic temperature-compensation ('Atc')
An exact temperature compensation is important for a reliable wood-moisture-measuring. These devices feature a high
quality thermocouple-input for type k thermocouples. Thus you could connect common surface-temperature-probes –
The needed measuring-time ‘afield’ will be drastically lowered compared to common (non-surface-) temperature-
probes. The used temperature-value therefore is:
Menu
Used temperature-value
Aux. Display
Atc on
Temperature-probe connected
Temperature-measuring through connected probe
arrow ‘T extern‘
No temperature-probe connected
Device-internal temperature-measuring
Atc off
Independent from temperature-
probe
Manual input of temperature: shortly press Temp-Button
then use (key 2) or (key 5) to input the
temperature confirm selection with ‘Store‘(key 6)
When connecting a probe that is not insulated you must have to observe not touching the wood or
the electrodes nearby the unshielded electrode. We suggest using our insulated probe
GTF38 (already included in standard case sets SET38HF and SET38BF).

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5.6 Measuring in wood: Measuring with two measuring-needles
Normally wood is measured with measuring-needles. Used electrodes: impact-electrode GSE91 or GSG91,
reciprocating piston electrode GHE91. For measuring wood, punch in the measuring-needles across to the wood-grain,
having a good contact between the needles and the wood (measuring along wood-grain deviates minimal)
Select correct wood-sort (refer to Appendix A).
Ensure measuring the correct temperature (see chapter 5.5).
Hint: The special GTF38 temperature-probe can be stuck into a hole punched in with the
electrode before (see picture on left).Now read the measuring-value or when having
activated the auto-hold-function initiate a new measuring by pressing Store/(button 6) .
The measured resistance will be extremely high when measuring dry wood (<15%) thus
the measuring will need more time to achieve its final value. Among other things static
discharge could momentarily falsify the measuring. Therefore beware of static discharge
and wait long enough until a stable measuring value is displayed (unstable: “%“ blinking)
or use the auto-hold-function (see chapter 5.4 Auto-Hold function).
Most accurate measurements can be carried out within the range of 6 to 30%.
Beyond this range the acquirable accuracy will lessen, but the device will deliver
reference values still sufficient for the practitioner.
Reciprocating piston
electrode GHE91 with
temperature-probe GTF38
It is measured between the measuring-needles insulated among each other. Requirements for an exact measurement:
-choose right correct place to measure: place should be free of irregularities like resin–clusters, knurls, rifts, etc.
-choose correct depth: Recommendation for trimmed timber: punch in the needles up to 1/3 of the material
thickness.
-Perform multiple measurements: the more measurements will be averaged, the more exact the result will be.
-Pay attention to temperature-compensation: the temperature-probe should be measuring the temperature of the
moisture-measuring-place when measuring with external temperature-probe (Atc on).
Without temperature-probe: let the device adapt to the temperature of the wood (Act on) or enter the exact
temperature manually (Act off).
Frequent sources of errors:
-Attention with oven-dried wood: the moisture dispersion may be irregular, often in the core is more moisture than on
the edge.
-Surface-moisture: The wood-edge could be more humid than the core if the wood had been stored outside and e.g.
was in rain.
-Wood preservative and other treatment could falsify the measuring.
-Fouling at the connections and round the needles could result in erroneous measurement, especially with dry wood.
5.7 Split log firewood measuring
For the firewood measuring there is a Average value calculation function integrated. The function calculates the
average value of 3 sequential measuring. Combined with the method described in the following, a reliable measuring of
split logs is possible.
5.7.1 Presetting
Auto Hold on: Automatic measurement
3-Pt on:Average function on
Common firewood specimens can be preset via the “Sort“-Menu, e.g.:
Sor.1 h.460 Spruce
Sor.2 h.206 Pine
Sor.3 h.86 Beech
Sor.4 h.60 Birch
Sor.5 h.401 Group hard wood Beech Birch Oak Ash
Sor.6 h.402 Group soft wood Pine, Spruce Fir
Sor.7 h.461 wood chips with GSF 50 or GSF 50 TF
Sor.8 .ref internal reference, e.g. for monitoring of the precision
Please refer to chapter 4 “Device configuration”.
The specific sort has to be chosen before measuring getroffen werden
5.7.2 Sampling
Choice of representative logs out of stack:
To be able to rate the stack, several logs from different positions should be measured (depending on
position: Top, bottom, weather side...)
The Logs should be free of anomalies like branches, cracks, pitch pockets.
Log size:
The logs to be measured should at least have a width 0f 10 cm and a length of 25 cm.

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5.7.3 Measuring
Split the log:
Use an suitable axe for splitting. Fast working splitting machines can produce heat which may falsify the
measuring.
Preparation of core temperature measuring of log:
Drive in the impact electrode, put temperature probe into the generated hole.
Three measuring values have to be taken at the freshly split surface,
2 measuring spots should have 5 cm distance
from cut side, the third should be placed in the
center.
Drive in the needles sufficiently deep( > 5mm) and
across the fibre direction
Measuring procedure:
Step
Action
Description
Display
Measuring 1
Drive in needles
Start measuring
press
Measuring value 1 will be
automatically taken
Measuring stable
Instrument is ready for
next step
Measuring 2
Drive in needles
Start measuring
press
Measuring value 2 will be
automatically taken
Measuring stable
Instrument is ready for
next step
Measuring 3
Drive in needles
Start measuring
press
Measuring value 3 will be
automatically taken
Measuring stable
Average out of the 3 will
be displayed
e.g.
Return to continuous
measuring display
press

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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.