Decagon Devices 5TE Manual de usuario
5TE
Water Content, EC
and Temperature Sensors
Operator’s Manual
Ve r s i o n 2
©2008 Decagon Devices, Inc.
All rights reserved.
Decagon Devices, Inc.
2365 NE Hopkins Court
Pullman WA 99163
www.decagon.com
5TE Operator’s Manual
Table of Contents
i
Contents
1. Introduction . . . . . . . . . . . . . . . . . .1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . 2
Warranty Information . . . . . . . . . . . . . . . . . . . . . . . 3
Seller’s Liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. About the 5TE . . . . . . . . . . . . . . . . 4
Background Info . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Theory . . . . . . . . . . . . . . . . . . . . . 6
Volumetric Water Content . . . . . . . . . . . . . . . . . . . 6
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Electrical Conductivity . . . . . . . . . . . . . . . . . . . . . . . 7
Converting Bulk EC to Pore EC . . . . . . . . . . . . . . 8
Pore Water vs. Solution EC . . . . . . . . . . . . . . . . . . . 9
4. Calibration . . . . . . . . . . . . . . . . . . 11
Dielectric Permittivity . . . . . . . . . . . . . . . . . . . . . . . . 11
Mineral Soil Calibration . . . . . . . . . . . . . . . . . . . . . 11
Calibration in Non-Soil Media . . . . . . . . . . . . . . . 12
5. Connecting Sensors . . . . . . . . . . .13
Using the 5TE with Em50/50R data loggers. . . . 13
3.5mm Stereo Plug Wiring . . . . . . . . . . . . . . . . . . . 14
Extending sensor cables . . . . . . . . . . . . . . . . . . . . . 14
Connecting to a non-Decagon Data logger . . . . . 15
Logger Communications . . . . . . . . . . . . . . . . . . . . . 16
5TE Operator’s Manual
Table of Contents
ii
Dielectric Permittivity . . . . . . . . . . . . . . . . . . . . . . . 17
Electrical Conductivity . . . . . . . . . . . . . . . . . . . . . . 17
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6. Installing the Probes . . . . . . . . . .19
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Removing the Probes . . . . . . . . . . . . . . . . . . . . . . . 21
Multiple Probe Installation . . . . . . . . . . . . . . . . . .22
7. Campbell Scientific Programs . . 23
8. Troubleshooting&Sensor Care . 24
Datalogger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Probes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Sensor Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Cleaning Method . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Declaration of Conformity . . . . . . 27
5TE Operator’s Manual
1. Introduction
1
1. Introduction
Thank you for choosing Decagon’s 5TE for measuring water
content, temperature, and EC. This manual is designed to help
you understand the probe’s features and how to use this
device successfully.
Specifications
Volumetric water content:
Range:
Apparent dielectric permittivity (εa): 1 (air) to 80 (water)
Resolution:
ε
a:0.1
ε
a(unitless) from 1-20, <0.75
ε
a(unitless) from 20-80
VWC: 0.0008 m3/m3(0.08% VWC) from 0 to 50% VWC
Accuracy:
(
ε
a): ±1
ε
a(unitless) from 1-40 (soil range), ±15% from 40-80
(VWC):
• Using Topp equation: ±0.03 m3/m3(±3% VWC) typical
in mineral soils that have solution electrical conductivity <
10 dS/m
• Using medium specific calibration, ±0.01 - 0.02 m3/m3
(± 1-2% VWC) in any porous medium
Electrical Conductivity (bulk):
Range:
0-23 dS/m (bulk)
Resolution: 0.01 dS/m from 0 to 7 dS/m, 0.05 dS/m from 7
to 23 dS/m
Accuracy: ±10% from 0 to 7 dS/m, user calibration required
above 7 dS/m
5TE Operator’s Manual
1. Introduction
2
Temperature
Range: -40-50 °C
Resolution: 0.1 °C
Accuracy: ±1 °C
General
Dimensions: 10 cm (1) x 3.2 cm (w) x 0.7 cm (d)
Prong Length: 5.2 cm
Dielectric Measurement Frequency: 70 MHz
Measurement Time: 150 ms (milliseconds)
Power requirements: 3.6 - 15 VDC, 0.3 mA quiescent, 10
mA during 150 ms measurement
Output: RS232 or SDI 12 (contact Decagon for information
on SDI-12 mode)
Operating Temperature: -40-50 °C
Connector types: 3.5 mm “stereo” plug or stripped and
tinned lead wires
Cable Length: 5m standard; custom cable length available
upon request
Datalogger Compatibility (not exclusive):
Decagon: Em50, Em50R
Campbell Scientific: Any logger with serial I/O (CR10X,
CR850, 1000, 3000, etc.)
Contact Information
If you need to contact Decagon:
•Call us at 800-755-2751 or (509) 332-2756
•Fax us at (509) 332-5158
•E-mail us at support@decagon.com.
5TE Operator’s Manual
1. Introduction
3
Warranty Information
All Decagon products have a 30-day satisfaction guarantee
and a one-year warranty.
Seller’s Liability
Seller warrants new equipment of its own manufacture against
defective workmanship and materials for a period of one year
from date of receipt of equipment (the results of ordinary
wear and tear, neglect, misuse, accident and excessive deterio-
ration due to corrosion from any cause are not to be consid-
ered a defect); but Seller’s liability for defective parts shall in
no event exceed the furnishing of replacement parts F.O.B. the
factory where originally manufactured. Material and equip-
ment covered hereby which is not manufactured by Seller shall
be covered only by the warranty of its manufacturer. Seller
shall not be liable to Buyer for loss, damage or injuries to per-
sons (including death), or to property or things of whatsoever
kind (including, but not without limitation, loss of anticipated
profits), occasioned by or arising out of the installation, opera-
tion, use, misuse, nonuse, repair, or replacement of said mate-
rial and equipment, or out of the use of any method or
process for which the same may be employed. The use of this
equipment constitutes Buyer’s acceptance of the terms set
forth in this warranty. There are no understandings, represen-
tations, or warranties of any kind, express, implied, statutory
or otherwise (including, but without limitation, the implied
warranties of merchantability and fitness for a particular pur-
pose), not expressly set forth herein.
5TE Operator’s Manual
2. About the 5TE
4
2. About the 5TE
The 5TE is designed to measure the water content, electrical
conductivity, and temperature of soil and growing media.
Using an oscillator running at 70 MHz, it measures the dielec-
tric permittivity of soil to determine the water content. A ther-
mistor in thermal contact with the probe prongs provides the
soil temperature, while the screws on the surface of the sensor
form a two-probe electrical array to measure electrical con-
ductivity.
Background Info
In 2006, Decagon incorporated research from its EC-5 volu-
metric water content sensor into the ECH2O-TE, a sensor
which measured volumetric water content, temperature, and
electrical conductivity. The new 5TE uses the same theory as
the ECH2O-TE, but the location of the EC measurement is in
the stainless steel screws instead of gold traces. The use of
stainless steel screws has made the 5TE a more robust sensor.
Additionally, the 5TE utilizes a 5 point dielectric calibration to
provide dielectric permittivity measurements far more accu-
rate than the previous ECH2O-TE.
5TE Operator’s Manual
2. About the 5TE
5
Figure 1: 5TE Components
5TE Operator’s Manual
3. Theory
6
3. Theory
Volumetric Water Content
The 5TE probe uses an electromagnetic field to measure the
dielectric permittivity of the surrounding medium. The probe
supplies a 70 MHz oscillating wave to the probe prongs that
charges according to the dielectric of the material. The stored
charge is proportional to soil dielectric and soil volumetric
water content. The 5TE microprocessor measures the charge
and outputs a value of dielectric permittivity from the probe.
Temperature
The 5TE uses a surface-mounted thermistor to take tempera-
ture readings. It is located underneath the probe overmold,
next to one of the prongs, and will read the temperature of the
prong surface. The 5TE will output temperature in °C unless
otherwise stated in your preferences file in either the ECH2O
DataTrac or ECH2O Utility programs.
It is important to note that if the black plastic overmold of the
probe is in direct sunshine, the temperature measurement may
read high. Exposure of the overmold to solar radiation will
also drastically decrease the life expectancy of the sensor. We
do not recommend that the sensor be installed with the over-
mold in the sun.
Otros manuales para 5TE
1
Tabla de contenidos
