Campbell Scientific DMM600 Duff Moisture Meter - Manual (Page 15)

DMM600 Duff Moisture Meter
7.3.3 Display
A two-line, 16-character LCD provides measurement results. When the
DMM600 is initially turned on, the display shows:
DMM600
Compress sample
The following is displayed after the sample is compressed and measured.
Std Cal: xx%
Freq: xx.xMHz
The water content measurement using the standard calibration is listed next to
StdCal. The frequency from the measurement circuit is listed next to Freq.
If a user-defined calibration is loaded in the DMM600, the following will also
be displayed:
name Cal: xx%
Freq: xx.xMHz
Where name is the name entered for the user-defined calibration as specified in
the PCDMM software. The display will alternate every 3 seconds between the
standard and user-defined calibration.
7.3.4 Serial Port
The DMM600 serial port is used for direct connection to the serial port of a
computer using a 9-pin serial cable. The port should be kept covered with the
plastic cover to protect from damage when not being used. PCDMM is the
interface software.
7.4 Water Content Measurement
7.4.1 Gravimetric and Volumetric Water Content
The DMM600 is sensitive to water content on a volume basis, i.e. volumetric
water content. Volumetric water content is the volume of water in a given
volume of material. Gravimetric water content is a weight-basis parameter and
is the ratio of the mass of water to the mass of the material with no water.
Volumetric and gravimetric water content are related by the bulk density of the
material. Multiplying gravimetric water content by material bulk density
yields volumetric water content.
The choice of water content description, whether gravimetric or volumetric, is
largely traditional in different professions. It is important to understand the
difference and how to convert between them.
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