Campbell CS616 Owner's manual

COMPONENTS
CS616
Water Content Reectometer
High Accuracy
and Precision
Designed for long-term monitoring
Overview
The CS616 measures the volumetric water content (VWC) of
porous media (such as soil) from 0% to saturation. The probe
outputs a megahertz oscillation frequency, which is scaled down
and easily read by a Campbell Scientic datalogger.
www.campbellsci.com/cs616-l
Benets and Features
Compatible with most Campbell Scientic dataloggers*
High accuracy and high precision
Fast response time
Designed for long-term unattended water content monitoring
Compatible with AM16/32-series multiplexers allowing
measurement of multiple sensors
Probe rods can be inserted from the surface or buried at any
orientation to the surface
questions & quotes: 435.227.9000
Technical Description
The CS616 is comprised of two 30 cm-long stainless steel rods
connected to the measurement electronics. The circuit board is
encapsulated in epoxy, and a shielded four-conductor cable is
connected to the circuit board to supply power, enable probe,
and monitor the output.
The CS616 uses the time-domain measurement method to
measure VWC; a reectometer (cable tester) such as the TDR100
is not required. This method consists of the CS616 generating an
electromagnetic pulse. The elapsed travel time and pulse reec-
tion are then measured and used to calculate soil volumetric
water content.
Response Characteristics
The signal propagating along the parallel rods of the CS616
is attenuated by free ions in the soil solution and conductive
constituents of the soil mineral fraction. In most applications,
the attenuation is not enough to aect the CS616 response to
changing water content, and the response is well described by
the standard calibration. However, in soil with relatively high soil
electrical conductivity levels, compacted soils, or soils with high
clay content, the calibration should be adjusted for the specic
medium. Guidance for making these adjustments is provided in
the operating manual.
*e CS616 is not compatible with our CR200(X)-series, CR7, or CR9000X dataloggers. However, a similar sensor, the CS625, has been
developed specically for our CR200(X)-series dataloggers. e operating system of older dataloggers might need to be upgraded. Operating
system upgrades are available, at no charge, from: www.campbellsci.com/downloads
CS616
CS616
CS616

Campbell Scientic, Inc.
|
815 W 1800 N
|
Logan, UT 84321-1784
|
[phone]
|
www.campbellsci.com
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RF Considerations
The RF emissions are below FCC and EU limits as specied in
EN61326 if the CS616 is enabled less than 0.6 ms, and measure-
ments are made less frequently than once a second. External RF
sources can also aect the CS616 operation. Consequently, the
CS616 should be located away from signicant sources of RF
such as ac power lines and motors.
© 2002, 2013
Campbell Scientic, Inc.
August 15, 2013
Ordering Information
Water Content Reectometer
CS616-L Water Content Reectometer with user-specied cable length.
Enter cable length, in feet, after -L. Recommended cable
length is 25, 50, 75, or 100 ft (8, 15, 23, or 31 m); maximum
length is 1000 ft (300 m). A cable termination option is
required (see below).
Cable Termination Options (choose one)
-PT Cable terminates in pigtails for direct connection to the
datalogger’s terminals.
-PW Cable terminates in a connector for attachment to a
prewired enclosure.
Installation Tool
CS650G Rod Insertion Guide Tool with Pilot Rod
The CS650G makes insert-
ing CS616 easier in dense
or rocky soils. This tool can
be hammered into the
soil with force that might
damage the sensor if the
CS650G were not used.
It makes pilot holes into
which the rods of the sen-
sors can then be inserted.
Specications
Probe-to-Probe Variability: ±0.5% VWC in dry soil, ±1.5% VWC
in typical saturated soil
Accuracy: ±2.5% VWC using standard calibration with bulk elec-
trical conductivity of ≤0.5 dS m-1, bulk density of ≤1.55 g cm-3,
and measurement range of 0% VWC to 50% VWC
Precision: better than 0.1% VWC
Resolution: 0.1% VWC
Output: ±0.7 V square wave with frequency dependent
on water content
Current Drain: 65 mA at 12 Vdc (when enabled);
45 μA (quiescent typical)
Power Supply Voltage: 5 Vdc minimum; 18 Vdc maximum
Enable Voltage: 4 Vdc minimum; 18 Vdc maximum
Electromagnetic: CE compliant; meets EN61326 requirements
for protection against electrostatic discharge
Rod Dimensions
Length: 300 mm (11.8 in)
Diameter: 3.2 mm (0.13 in)
Spacing: 32 mm (1.3 in)
Probe Head Dimensions
Height: 85 mm (3.3 in)
Width: 63 mm (2.5 in)
Depth: 18 mm (0.7 in)
Weight
Probe without cable: 280 g (9.9 oz)
Cable: 35 g per m (0.38 oz per ft)