Campbell Scientific DOT600 Roadbed Water Content Meter - Manual (Page 7)

DOT600 Roadbed Water Content Meter
3. Specifications
Power
Battery
2.9 Ahr rechargeable sealed lead-acid battery
Operating temperature range: -20°C to 60°C
Standby charge retention at 20°C for one year = 95%
Lifetime approximately 500 cycles with discharge to 50% followed by
recharge.
See section Power System
Scale
Capacity = 1000 g
Accuracy =
±0.032%
Repeatability = 0.02% FS
The scale has overload protection in both the up and down directions during
shipping. But it only has overload protection in the down direction during use.
Water Content Measurement
Resolution = 1% volumetric water content
Precision = 0.75% volumetric water content
Resolution is the minimum change in the measured parameter, water content,
that the sensor can repeatedly detect.
Precision is the expected range for repeated measurements on the same sample.
Accuracy is defined by comparing DOT600 measured water contents to
independently determined values. The independent method is water content by
gravimetric method (weighing sample before and after oven drying).
The DOT600 water content measurement uses a calibration to convert sensor
output period to volumetric water content. This calibration was derived at the
factory for various soil types. The calibration coefficients used are determined
by the material type selected by the user. Repeated measurements on the sandy
loam soil over the water content range from air dry to about 70% saturation
show deviations from independent measurements of less than
±1.5%
volumetric water content.
Since the gravimetric water content measurement uses sample volume and
weight to convert from measured volumetric water content, the accuracy of the
gravimetric water content will be less than the volumetric value because of
inherent errors of the volume and weight measurements.
Sample Volume and Applied Force Measurement
Sample Volume
±1.5% for compressed sampled with thickness between .400 in to 1.000 in.
Sensitive Volume
The electromagnetic field penetrates the sample 0.39 in. Sensitive volume is
about 3.5 in
3 .
Applied vertical stress range and accuracy
Applied vertical stress: 0 to 45 PSI.
Applied vertical stress measurement accuracy: 1.7 PSI.
3