Decagon 10HS Operator's Manual

10HS

Soil Moisture Sensor

Operator’s

Manual

Version 3

Decagon Devices, Inc.

2365 NE Hopkins Court

Pullman WA 99163

[phone]

fax: [phone]

www.decagon.com

Trademarks

10HS is a registered trademark of

Decagon Devices, Inc.

©2008-2010 Decagon Devices, Inc.

Table of Contents

1. Introduction .................................................1

Specifications ........................................................... 1

Customer Support ................................................... 2

Warranty Information .............................................. 3

Seller’s Liability ........................................................ 3

2. About the 10HS ...........................................4

Background Info ...................................................... 4

3. eory ..........................................................5

4. Installing the Sensor ....................................6

5. Collecting Data ............................................8

Data logger Requirements ........................................ 8

6. Calibration .................................................11

Dielectric calibration ............................................. 11

Mineral Soil Calibration ........................................11

7. Sample Programs ........................................13

Declaration of Conformity .............................17

Index ..............................................................18

10HS--Soil Moisture Sensor

1. Introduction

1

1. Introduction

ank you for choosing the 10HS soil water content sensor. is in­novative sensor will enable you to monitor volumetric water content
of soil accurately and affordably. is manual is designed to help you
understand the sensor’s features and how to use this device success­fully.

Specifications

Range:

Apparent dielectric permittivity (e

a

): 1 (air) to 50

Soil volumetric water content (VWC): 0 – 0.57 m3/m3 (0 -57% VWC)

Accuracy:

(ea): ± 0.5 from ea of 2 to 10, ±2.5 from e

a

of 10 to 50 (VWC):
VWC: Using standard calibration equation: ± 0.03 m3/m3 (±
3% VWC) typical in mineral soils that have solution
electrical conductivity < 10 dS/m

Using soil specific calibration, ± 0.02 m3/m3 (± 2%
VWC) in any soil

Resolution:

e

a

: 0.1 from ea of 1 to 30, 0.2 from e

a

of 30 to 50

VWC: 0.0008 m3/m3 (0.08% VWC) in mineral soils from 0 to

0.50 m3/m3 (0-50% VWC)

Measurement Time: 10 ms (milliseconds)

Power requirements: 3VDC @ 12mA to 15 VDC @ 15 mA

Output: 300 – 1250 mV, independent of excitation voltage

Operating Temperature: 0 – 50 °C

Survival Temperature: -40 to 50 °C

2

10HS--Soil Moisture Sensor

1. Introduction

Connector types: 3.5 mm stereo plug or stripped and tinned leads.

Cable length: 5 m standard; custom cable length available upon

request

Datalogger Compatibility (non-exclusive):

Decagon: Em50, Em50R, Em5b, ProCheck handheld reader.
Campbell Scientific: CR10X, 21X, 23X, CR850, 1000, 3000, etc
Other: Any data acquisition system capable of switched 3 to15 V

excitation and single ended voltage measurement at 12 bit or better
resolution

Customer Support

If you ever need assistance with your 10HS, or if you just have
questions or feedback, there are several ways to contact us:

NOTE: If you purchased your 10HS through a distributor, please
contact them for assistance.

E-mail
[e-mail]

Please include your name, contact information, instrument serial
number(s), and a description of your problem or question.

[e-mail]

Please include your name, address, phone number, the items you
wish to order and a purchase order number. Credit card numbers
should always be called in.

Phone

1-800-755-2751 (USA and Canada Only)
1-509-332-2756 (International)

Our Customer Support and Sales Representatives are available
Monday thru Friday from 8am to 5pm (Pacific Standard Time).

10HS--Soil Moisture Sensor

1. Introduction

3

Fax

1-509-332-5158

Warranty Information

e 10HS sensors 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 deterioration due to corro­sion from any cause are not considered to be 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 equipment covered hereby which is not man­ufactured by the Seller shall be covered only by the warranty of its
manufacturer. Seller shall not be liable to Buyer for loss, damage,
or injuries to persons (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,
operation, use, misuse, nonuse, repair, or replacement of said ma­terial and equipment, or out of the use of any method or process
for which the same may be employed. e use of this equipment
constitutes Buyer’s acceptance of the terms set forth in this war­ranty. ere are no understandings, representations, or warranties
of any kind, express, implied, statutory or otherwise, (including,
but without limitation, the implied warranties of merchantability
and fitness for a particular purpose), not expressly set forth herein.

4

10HS--Soil Moisture Sensor

2. About the 10HS

2. About the 10HS

e 10HS measures the dielectric constant of the soil in order
to find its volumetric water content (VWC). Since the dielec­tric constant of water is much higher than that of air or soil
minerals, the dielectric constant of the soil is a sensitive mea­sure of volumetric water content. e 10HS has a low power
requirement and very high resolution. is gives you the abil­ity to make as many measurements as you want (i.e. hour­ly) over a long period of time with minimal battery usage.

Background Info

In 2005, the Decagon research team optimized a sensor oscillator fre­quency for very high accuracy soil moisture measurements. e first sen­sor to incorporate the new frequency was our EC-5 sensor. It quickly
became the most popular soil moisture sensor we’ve designed. e new
10HS sensor uses the same 70MHz oscillator frequency as the EC-5 but
has a larger soil volume and requires no special calibration when used
with other systems. New features of the 10HS include:

 •Onboardvoltageregulatorallowingyoutopowerthe

sensor with a wide range of excitation voltages (3-15
VDC) without changing the calibration

 •Largesensing(1100cubiccentimeters)allowingyouto

have a more representative measurement of soil VWC

e 10HS sensor runs at the same oscillator frequency that has given the
EC-5 exceptional performance in soils (Kizito et.al, 2008, Bogena et. al,

2007). We recommend the 10HS sensor for mineral soil applications
where soil heterogeneity is a concern. However, we continue to recommend
the smaller EC-5 sensor for soilless substrate applications or applications
where VWC measurements on smaller scales (e.g. near surface measure­ments, laboratory column studies, greenhouse applications) are desired.