Decagon Devices AccuPAR LP-80 User manual

AccuPAR
PAR/LAI ceptometer
model LP-80
Operator’s Manual
Ve r si o n 1 . 0
Decagon Devices, Inc.

Decagon Devices, Inc.
950 NE Nelson Court
Pullman, WA 99163
tel: [phone]
fax: [phone]
www.decagon.com/lp80
[e-mail]
Trademarks
AccuPAR and Ceptometer are
registered trademarks of Decagon
Devices, Inc. © 2003

LP-80
Table of Contents
i
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 1
Customer Service and Tech Support . . . . . . . . 1
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Seller’s Liability . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Repair Instructions . . . . . . . . . . . . . . . . . . . . . . . 3
2. About the LP-80 . . . . . . . . . . . . . . . . . . . . . 5
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Overview of the LP-80 . . . . . . . . . . . . . . . . . . . 6
Components of the LP-80 system . . . . . . . . . . . 7
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Keyboard Operation . . . . . . . . . . . . . . . . . . . . . 8
Turning on the instrument . . . . . . . . . . . . . . . . . 9
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . .11
PAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Tau (t) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
LAI (L) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
External Sensor . . . . . . . . . . . . . . . . . . . . . . . . . 13
Zenith Angle (z) . . . . . . . . . . . . . . . . . . . . . . . . . 13
Fraction of Beam Radiation (Fb) . . . . . . . . . . . 14
Leaf Distribution Parameter (x) . . . . . . . . . . . . 14
4. PAR/LAI Menu . . . . . . . . . . . . . . . . . . . . 17
Taking Measurements . . . . . . . . . . . . . . . . . . . 17
5. Log Menu . . . . . . . . . . . . . . . . . . . . . . . . . 20
7. File Menu . . . . . . . . . . . . . . . . . . . . . . . . . 22
View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

LP-80
Table of Contents
ii
Send . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
New . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Delete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Delete All . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
7. Setup Menu . . . . . . . . . . . . . . . . . . . . . . . 30
Set Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . .34
Calibrate Probe . . . . . . . . . . . . . . . . . . . . . . . . .34
External Sensor Const. . . . . . . . . . . . . . . . . . . .36
About . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
8: PAR and LAI Theory . . . . . . . . . . . . . . . . 38
PAR (photosynthetically active radiation) . . 38
Average and Intercepted PAR . . . . . . . . . . . .38
Using PAR to determine Leaf Area Index . . .45
Extinction Coefficient and
Canopy Structure . . . . . . . . . . . . . . . . . . . . . . .49
LAI measurements and
Non-Random Distribution . . . . . . . . . . . . . . . .57
Zenith Angle and Equation of Time . . . . . . . .62
9. Measurement Tips . . . . . . . . . . . . . . . . . . 67
Above Canopy (External) Sensor . . . . . . . . .67
Sample Size . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
Clumping in Canopies . . . . . . . . . . . . . . . . . . . .68
10. Care and Maintenance . . . . . . . . . . . . . 70
Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Cleaning the Probe and Controller . . . . . . . . 71
Re-calibration . . . . . . . . . . . . . . . . . . . . . . . . . . 71
General Precautions . . . . . . . . . . . . . . . . . . . . .72

LP-80
Table of Contents
iii
Appendix A:
External Sensor Information . . . . . . . . . . . 73
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . .73
Spectral Response . . . . . . . . . . . . . . . . . . . . . .73
Cosine Response . . . . . . . . . . . . . . . . . . . . . . . .74
Temperature Response . . . . . . . . . . . . . . . . . .74
Long-term stability . . . . . . . . . . . . . . . . . . . . . .75
Appendix B: Further Readings . . . . . . . . . 76
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83

AccuPAR LP-80
Introduction
1
1. Introduction
Welcome to Decagon’s AccuPAR model LP-80 PAR/
LAI Ceptometer. The AccuPAR measures
Photosynthetically Active Radiation (PAR) in the
400-700nm waveband, and can invert these readings
to give you Leaf Area Index for your plant canopy.
This manual is designed to help you accomplish
your research goals, and understand how to get the
most out of your AccuPAR.
Customer Service and Tech Support
When contacting us via fax or email, include the
following information: Your AccuPAR’s serial
number, your name, address, phone and fax
number, and a description of your problem
Phone:
Call Monday through Friday, between 8 a.m. and 5
p.m. PST.
US and Canada (toll-free): 1-800-755-2751 .
Outside of the US and Canada: [phone].
Fax:
[phone].

AccuPAR LP-80
Introduction
2
E-mail:
[email protected].
Warranty
The AccuPAR has a one year warranty on parts and
labor. It is activated upon the arrival of the
instrument at your location.
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

AccuPAR LP-80
Introduction
3
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.
Repair Instructions
If your AccuPAR needs to be sent in for service or
repair, call Decagon at [phone] or 1-800-
755-2751 (US and Canada).We will ask you for
your address, phone number, and serial number.
For non-warranty repairs, we will also ask for a
purchase order number, a repair budget, and billing
address.
When shipping your instrument back to us, include
a document listing the complete shipping address,
name and department of the person responsible for
the instrument, and (most importantly) a description
of the problem. This will better help our technicians
and our shipping department to quickly expedite
repair on your instrument and ship it back to you.
Pack your AccuPAR carefully. Ship it back in the
black carrying case, preferably inside a cardboard

AccuPAR LP-80
Introduction
4
box. Ship to:
Decagon Devices Inc.
950 NE Nelson Court
Pullman, WA 99163
Repair Costs:
Manufacturer’s defects and instruments under
warranty will be repaired at no cost. For non-
warranty repairs, costs for parts, labor, and shipping
will be billed to you. We have a $65 minimum
charge for repair that takes one hour or less. For
repair over one hour the labor rate is $65/hour.

AccuPAR LP-80
About the LP-80
5
2. About the LP-80
The AccuPAR model LP-80 is a menu-driven,
battery-operated linear PAR ceptometer, used to
measure light interception in plant canopies, and to
calculate Leaf Area Index (LAI). It consists of an
integrated microprocessor-driven datalogger and
probe. The probe contains 80 independent sensors,
spaced 1cm apart. The photosensors measure PAR
(Photosynthetically Active Radiation) in the 400-
700nm waveband. The AccuPAR displays PAR in
units of micromols per meter squared per second
(µmol m-2s-1). The instrument is capable of hand-
held or unattended measurement.
Specifications
Operating Environment:
• 0° to 50° C (32°-122° F)
• 100% relative humidity
Probe Length: 86.5 cm
Number of sensors: 80
Overall Length: 102 cm (40.25 in)
Probe Cross-Section: 19cm x 9.5cm (.75 x .375 in)
Microcontroller dimensions: 15.8 x 9.5 x 3.3cm (6.2
x 3.75 x 1.3 in.)
PAR Range: 0 to >2,500µmol m-2s-1