Campbell EasyAG SDI-12 User manual

INSTRUCTION MANUAL
EasyAG® Profile Probes
February 2015
Copyright © 2002-2009
Campbell Scientific, Inc.
EasyAG
®
and EnviroSMARTare trademarks of Sentek Pty. Ltd.

Assistance
Products may not be returned without prior authorization. The following
contact information is for Canadian and international clients residing in
countries served by Campbell Scientific (Canada) Corp. directly. Affiliate
companies handle repairs for clients within their territories. Please visit
www.campbellsci.ca to determine which Campbell Scientific company serves
your country.
To obtain a Returned Materials Authorization (RMA), contact CAMPBELL
SCIENTIFIC (CANADA) CORP., phone [phone]. After a
measurement consultant determines the nature of the problem, an RMA
number will be issued. Please write this number clearly on the outside of the
shipping container. Campbell Scientific’s shipping address is:
CAMPBELL SCIENTIFIC (CANADA) CORP.
RMA#_____
14532 131 Avenue NW
Edmonton, Alberta T5L 4X4
Canada
For all returns, the client must fill out a “Statement of Product Cleanliness and
Decontamination”form and comply with the requirements specified in it. The
form is available from our web site at www.campbellsci.ca/repair. A
completed form must be either emailed to [e-mail] or faxed to
[phone]. Campbell Scientific (Canada) Corp. is unable to process any
returns until we receive this form. If the form is not received within three days
of product receipt or is incomplete, the product will be returned to the client at
the client’s expense. Campbell Scientific (Canada) Corp.f reserves the right to
refuse service on products that were exposed to contaminants that may cause
health or safety concerns for our employees.

i
Table of Contents
PDF viewers: These page numbers refer to the printed version of this document. Use the
PDF reader bookmarks tab for links to specific sections.
1. General .......................................................................1
2. Absolute Data.............................................................1
3. Relative Data ..............................................................1
4. Measurements............................................................1
4.1 Water Content ......................................................................................1
4.2 Salinity .................................................................................................2
5. Resolution and Accuracy..........................................2
5.1 Volumetric Water Content ...................................................................2
5.2 Salinity .................................................................................................2
6. Specifications.............................................................4
7. Installation..................................................................5
8. Probe Wiring...............................................................5
8.1 DI-12 Interface Wiring.........................................................................5
8.2 Cable Installation .................................................................................6
9. Datalogger Programming..........................................6
10. Care and Maintenance.............................................14
11. Acknowledgements .................................................14
Appendices
A. Normalization and Function Test..........................A-1
A.1 Normalization ................................................................................. A-1
A.1.1 Water Content Only ................................................................. A-2
A.1.2 TriSCAN Normalization .......................................................... A-4
A.2 Configuration Testing ..................................................................... A-5
B. Tube Installation.....................................................B-1
B.1 Introduction......................................................................................B-1
B.1.1 Soil Suitability ..........................................................................B-1
B.1.2 Sledgehammer Technique.........................................................B-1

Table of Contents
ii
B.1.3 Soil Sampler Extraction ........................................................... B-1
B.1.4 Air Gap Correction................................................................... B-1
B.2 Installation Tools............................................................................. B-2
B.3 Installation Procedure...................................................................... B-3
B.4 Removing Access Tubes ............................................................... B-12
C. Site Selection..........................................................C-1
D. SDI-12 Commands .................................................D-1
Figures
8-1. EasyAG£SDI-12 Interface ................................................................. 5
A-1. SDI-12 Interface Power Connection ............................................... A-1
A-2. SDI-12 Interface TTL Connection .................................................. A-1
A-3. IPConfig Utility Icon....................................................................... A-2
A-4. IPConfig Probe Configuration Window .......................................... A-2
A-5. IPConfig Probe Configuration Window for TriSCAN .................... A-4
A-6. IPConfig Configuration Test Window ............................................ A-5

1
EasyAG®
Soil Water Content Profile Probes
1. General
EasyAG®probes measure a profile of volumetric soil water content. EasyAG
50 probe measures at 10, 20, 30, and 50 cm. EasyAG 80 probe measures at 10,
30, 50, and 80 cm. TriSCAN versions of these probes also measure soil
salinity.
Irrigation scheduling, waste water treatment, and other applications requiring
continuous monitoring of water or water and ion movement in a soil profile
may benefit from EasyAG technology. Water content measurements can be
made in all soil types. Salinity measurements are restricted to sand, loamy
sand, and sandy loam soils.
2. Absolute Data
EasyAG probes calibrated for a particular site, including the textural layers of a
soil profile, will produce absolute and accurate data. Absolute data, however,
require that sensors be calibrated for each soil type and each soil horizon.
Absolute calibration is a costly and time consuming process, but must be done
if absolute data are required. A manual for absolute data calibration is
published by Sentek.
3. Relative Data
Relative data are produced by an EasyAG calibrated for a range of soil types,
and this calibration is used as a default calibration on all soil types. Readings
cannot be considered as absolute data, but instead reflect soil water and ion
changes used as decision criteria in soil management.
Relative water content data have been used since at least 1992 for irrigation
management, isolating factors such as depth of irrigation and rainfall, depth of
effective root zone, onset of crop water stress, and avoidance of water logging.
Economic gains achieved with soil profile management in commercial
agriculture and waste water management are typically made using the concept
of ‘relative’change in soil dynamics.
4. Measurements
Sensors are measured by the probe’s SDI-12 interface. The interface transmits
measurements to the datalogger. TriSCAN sensors provide two outputs, water
content and salinity. Both outputs can be presented as dynamic trend changes
over a chosen time scale. Acceptable time stamp data range from 00:00:00 as
midnight to 23:59:59.
4.1 Water Content
Sensor output is a dimensionless frequency (raw count) that is converted via a
normalization equation and then a default or user-defined calibration equation

EasyAG®Soil Water Content Profile Probes
2
into volumetric soil water content. The measurement unit is volumetric water
content (Vol %) or millimetres of water per 100 mm of soil. Acceptable data
range for scaled frequencies is >0 to 1.0. Water content measurements using
the default calibration range from 0 to 53%.
4.2 Salinity
Sensor output is a dimensionless frequency (raw count) that, in conjunction
with the water content output signal, is proportional to changes in soil water
content and salinity. A proprietary data model processes the changes of both
output signals simultaneously to reflect the changes in soil salinity. The output
of the data model is a nominal Volumetric Ion Content (VIC). Measurement
units of VIC can be quantitatively related (benchmarked) to the soil EC
through site-specific soil sampling and analysis.
Acceptable VIC data range from 1000 to 17,000. The effective salinity
measurement range is between 0 and 17 dS m-1 in sand, loamy sand, and sandy
loam textures (Australian Soil and Land Survey Field Handbook). Salinity
levels and soil textures outside this range are currently not supported by
TriSCAN.
5. Resolution and Accuracy
5.1 Volumetric Water Content
The sensor has a resolution of 0.1 mm of soil moisture. Consecutive readings
in equilibrated soil have a coefficient of variation of 0.1%. Accuracy of the
system is dependent upon the similarity of the soil site to that of the original
default soil type used by Sentek. Calibration coefficients based on this default
soil type are used in normal operation. If site-specific (quantitative) values are
required, then a calibration procedure is required to be performed (refer to
“Calibration of Sentek Probes” Manual). A high level of accuracy can be
attained with careful calibration.
5.2 Salinity
To date, statements on the resolution and accuracy of the salinity output can
only be made with regard to the particular type of sand that has been used to
develop the TriSCAN data processing models. These specifications do not
necessarily reflect the resolution and accuracy of the sensor on any other soil
types. Accuracy and precision of the sensor in the tested sand are as follows:
In saturated soil conditions at low EC 55 μS cm-1:G
Repeatable change of VIC to a resolution of 1 μS cm-1 (Accuracy
±1.8%)G
In saturated soil conditions at medium EC up to 5600 μS cm-1:G
Repeatable change of VIC to a resolution of 25 μS cm-1 (Accuracy
± 0.4%)
VIC can be related directly to a site-specific soil EC through the use of
Sentek’s Benchmarking Procedure.
The accuracy of any such relationships is dependent upon the accuracy and
competency with which this procedure is performed. In Sentek’s own field

EasyAG®Soil Water Content Profile Probes
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testing, strong relationships (r2=0.9) have been achieved. Refer to the
benchmarking section of the Sentek TriSCAN manual.
Precise temperature effects on salinity data output are currently unknown. It is
however, known that there is a minor positive relationship between VIC and
soil temperature. The salinity model currently does not include temperature
correction.

EasyAG®Soil Water Content Profile Probes
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6. Specifications
Feature
EasyAG
SDI-12
Maximum cable length to
logger or third party device
60 m (200 ft)*
Maximum sensors per
standard probe
4
Sensor Measuring Principle
High frequency capacitance
Output Options
SDI-12
Protocol options
SDI-12
Interface Measuring Principle
16 Bit pulse count
Output Resolution
16 Bit
Output Method
Serial data
Current Consumption
250 μA @ Sleep
66 mA @ Standby
100 mA @ Sampling
Reading range
Water Content/Salinity
0 to ~65%/0 to 17 dSm
-1
Temperature effects
r3% 5°C to 35°C
Operating temperature range
-20°C to +75°C
Time to read one sensor
1.1 seconds
Sphere of influence
99% of the reading is taken within a 10 cm
radius from the outside of th
e access tube
Sensor diameter
26.5 mm
Access tube diameter
32 mm
Probe length
50 cm (20 inches)
*
Based on SENSDI12CBL-L cable.