Decagon Devices Dielectric Leaf Wetness Sensor Owner's/operator's Manual

Operator’s Manual

Decagon Devices, Inc.

Version: February 29, 2016 — 11:10:55

LWS

Decagon Devices, Inc.

2365 NE Hopkins Court

Pullman WA 99163

Phone: [phone]

Fax: [phone]

Website: www.decagon.com

Email: [e-mail] or [e-mail]

Trademarks:

“ECH2O” is a registered trademark of Decagon Devices, Inc.

All Rights Reserved

c

2007-2014 Decagon Devices, Inc.

All Rights Reserved

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LWS CONTENTS

Contents

1 Introduction 1

1.1 Customer Support . . . . . . . . . . . . . . . . . . . . 1

1.2 About This Manual . . . . . . . . . . . . . . . . . . . 1

1.3 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.4 Seller’s Liability . . . . . . . . . . . . . . . . . . . . . . 2

2 About the Leaf Wetness Sensor 3

2.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . 3

3 Collecting Data 5

3.1 Installing the Sensor . . . . . . . . . . . . . . . . . . . 5

3.2 Data Logger Requirements . . . . . . . . . . . . . . . . 6

3.3 Adapter Cable Wiring . . . . . . . . . . . . . . . . . . 6

3.4 Extending the Sensor Leads . . . . . . . . . . . . . . . 7

3.5 UV Protection . . . . . . . . . . . . . . . . . . . . . . 7

4 Interpreting Data 8

4.1 Understanding Data from the Em50 . . . . . . . . . . 9

4.1.1 Processed Data File . . . . . . . . . . . . . . . 9

4.1.2 Unprocessed Data File . . . . . . . . . . . . . . 10

4.1.3 DataTrac3 File . . . . . . . . . . . . . . . . . . 11

4.2 Understanding Data from Other Data Loggers . . . . 11

5 LWS Theory 12

5.1 How the LWS Works . . . . . . . . . . . . . . . . . . . 12

5.2 How the LWS Mimics a Real Leaf . . . . . . . . . . . 12

6 Appendix A: Sample CSI Program 14

7 Declaration of Conformity 16

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LWS 1 INTRODUCTION

1 Introduction

Thank you for choosing Decagon’s Dielectric Leaf Wetness Sensor.
We designed this sensor to accurately and affordable measure the
duration of leaf-surface wetness. This manual should help you un­derstand the sensor features and how to use it successfully.

1.1 Customer Support

There are several ways to contact Decagon if you ever need assis­tance with your product, have any questions, or feedback. Decagon
has Customer Service Representatives available to speak with you
Monday through Friday, between 7 am and 5 pm Pacific time.

Note: If you purchased your sensor through a distributor, please con­tact them for assistance.

Email:
[e-mail] or [e-mail]

Phone:
509-332-5600

Fax:
509-332-5158

If contacting us by email or fax, please include as part of your mes­sage your instrument serial number, your name, address, phone, fax
number, and a description of your problem or question.

1.2 About This Manual

Please read these instructions before operating your sensor to ensure
that it performs to its full potential.

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1 INTRODUCTION LWS

1.3 Warranty

The Dielectric Leaf Wetness Sensor has a 30-day satisfaction guar­antee and a one-year warranty on parts and labor. Your warranty is
automatically validated upon receipt of the instrument.

Note: The one year service plan activates when Decagon ships the
instrument and not at the time of software installation.

1.4 Seller’s Liability

Seller warrants new equipment of its own manufacture against de­fective workmanship and materials for a period of one year from the
date of receipt of equipment.

Note: We do not consider the results of ordinary wear and tear,
neglect, misuse, or accident as defects.

The Seller’s liability for defective parts shall in no event exceed the
furnishing of replacement parts “freight on board” the factory where
originally manufactured. Material and equipment 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 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. The use of this equipment con­stitutes Buyer’s acceptance of the terms set forth in this warranty.
There 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.

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LWS 2 ABOUT THE LEAF WETNESS SENSOR

2 About the Leaf Wetness Sensor

The LWS measures leaf surface wetness by measuring the dielectric
constant of the sensor’s upper surface (see Section 5 for a more thor­ough explanation). It has a very low power requirement, which gives
you the ability to make as many measurements as you want over a
long period of time (such as a growing season) with minimal bat­tery usage. This sensor also has very high resolution, which gives
you the ability to detect very small amounts of water (or ice) on the
sensor surface. Water on the sensor surface does not need to bridge
electrical traces to be detected, as is common with resistance based
surface wetness sensors. This means that the LWS does not need
to be painted before use, which eliminates the need for individual
sensor calibration.

2.1 Specifications

Measurement Time: 10 ms

Power: 2.5 VDC @ 2 mA to 5 VDC @ 7 mA

Output: 320 to 1000 mV @ 3 V excitation

Operating Environment: -20 to 60◦C

Probe Dimensions: 11.2 cm x 5.8 cm x .075 cm

Cable Length: 5 m standard, extension cables are available

Connector Type: 3.5 mm plug or optional “pigtail” adapter (stripped

and tinned lead wires)

Data Logger Compatibility (not exclusive):

Decagon: Em50, Em50R
Campbell Scientific: CR10, 10X, 21X, 23X, 1000, 3000, 5000

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