Campbell CS650, User Manual

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User Manual
9
Volumetric Water Content using Topp Equation (m
3
/m
3
)
Range 5% to 50%
Accuracy†

3% VWC typical in
mineral soils where
solution EC

3 dS/m

3% VWC typical in
mineral soils where
solution EC

10 dS/m
Precision‡
<0.05%
Electrical Conductivity
Range Solution EC
0 to 3 dS/m 0 to 8 dS/m
Range Bulk EC
0 to 3 dS/m 0 to 8 dS/m
Accuracy†

(5% of r 0.05 dS/m)
Precision‡ 0.5% of BEC
Temperature
Soil Measurement Range
–10 to 70 °C
Operational Range 0 to 70 °C
Accuracy†

0.5

C for probe body buried in soil
Precision‡

0.02 °C
Sensing Volume* 7800 cm
3
3600 cm
3
* Sensing Volume approximately 7.5 cm radius around each probe rod and 4.5 cm
beyond the end of the rods
†Accuracy
specifications are based on laboratory measurements in a series of
solutions with dielectric permittivities ranging from 1 to 81 and solution electrical
conductivities ranging from 0 to 3 dS/m.
‡Precision
describes the repeatability of a measurement. It is determined for the
CS650 by taking repeated measurements in the same material. The precision of the
CS650 is better than 0.05 % volumetric water content and 0.01 dS/m electrical
conductivity.
7. Installation
If you are programming your datalogger with Short Cut , skip Section 7.3 ,
Datalogger Wiring
(p. 10)
, and Section 7.4 , Programming
(p. 11)
. Short Cut does this
work for you. See Section 4 , Quickstart
(p. 2)
, for a Short Cut tutorial.
7.1 Orientation and Placement
The CS650 measures the bulk dielectric permittivity, average volumetric water
content, and bulk EC along the length of the rods, which is 30 cm for the CS650
and 12 cm for the CS655. The probe rods may be inserted vertically into the soil
surface or buried at any orientation to the surface. The probe may be installed
horizontal to the surface to detect the passing of wetting fronts or other vertical
water fluxes.
The sensitive volume depends on the surrounding media. In soil, the sensitive
volume extends approximately 7.5 cm (3 in) from the rods along their length and
4.5 cm (1.8 in) beyond the end of the rods. Consequently, if the probe is buried
horizontally closer than 7.5 cm from the soil surface, it will include air above the
surface in its measurements and underestimate soil water content.