User manual

H60.0.71.6C-04 Manual Appendix GMH 38-LW1 / -LW2 page 3 of 8

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4 Product Description

4.1 Scope of supply

The scope of supply of the GMH 38-LW Sets includes:

measuring probe GSF 50 TFK or GSF 50 TF

Display instrument of GMH 38 series

with 9V battery and operating manual

Operating manual appendix GMH 38-LW1/-LW2

4.2 The measuring probe GSF 50 TF(K)

The resistance of the medium between the conical metal surfaces

(1) and (2) is measured. The medium being measured has to be

compressed well enough.

The best is, having a constant pressure onto the medium

during the measurement. Do not release handle during the

measuring, otherwise the contact to the medium can be inter-

rupted, in this case a to dry value would be measured.

Attention: Especially at bulk material stored outside or very wet

material, large distribution of the actual moisture values can ap-

pear.

It is best to do several measurements and taking the aver-

age in order to get meaningful results:

The measurement of wood chips or things like that is depending

on temperature. For an exact measuring result the temperature is

automatically compensated when using the suitable instrument

(e.g. GMH 3830). The temperature-measuring is done at the tip of

the probe (1), a sufficient time to adjust the sensors temperature

to the material has to be waited for.

Different measuring results are depending on different types of

material. Select correct material-group or material type before

measuring. Refer to operation manual of the connected measur-

ing device. When pushing in the probes, oscillating movements

have to be avoided. Otherwise hollows between the probes and

the material may falsify the measurement minimum immersion 100 mm

5 Unit conversion: moisture dry-and wetbasis

Older instruments (e.g. GMH 3830 before V1.4) cannot be switched from moisture content u to w, in this

case the wet basis moisture content can be calculated like following:

Wet-basis moisture w [%] = 100 * Moisture content u [%] / (100 + Moisture content u [%])

Example: 1 kg of wet wood, which contains 500 g of water has a moisture content u of 50%

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

wet-basis moisture content w [%]

moisture content u [%] = display of GMH 38x0

Conversion moisture content u - wet-basis moisture content w