Apogee SQ-326 Посібник користувача - Сторінка 2

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Quantum Sensor Models
A quantum refers to the amount of energy carried
by a photon. Apogee quantum sensors approximate
the quantity of photons
nanometers.
Photosynthesis is largely driven by
the number of photons between these wavelengths,
so this radiation is called the Photosynthetic Photon
Flux (PPF) and is measured in μmol m
Quantum Sensors
US Patent No. D519,860
Line Quantum Sensors
3 sensors, 50 cm length; SQ-313 (Sun), SQ-323 (Electric)
6 sensors, 50 cm length; 316 (Sun), SQ-326 (Electric)
10 sensors, 70 cm length; SQ-311 (Sun), SQ-321 (Electric)
Mounting the Sensor
Bolt: 10-32x5/8
Model AL-100
Orientation
between 400 and 700
-2
-1
s
.
Calibrated for electric light
SQ-120
Calibrated for sun light
SQ-110
2
Each sensor is equipped
with
a
mounting
Mount
the
sensor
level as possible.
changes in level can cause
measurement errors.
recommend
using
leveling plate
(model AL-100)
for
the
most
accurate
measurements. The sensor
should be mounted with the
cable pointing toward the
nearest magnetic pole to
minimize azimuth error.
S
N
N N
4
Cosine response
Some of the radiation coming into a sensor at low angles is reflected, which
causes low readings. The convex optical disc is designed to capture radiation
at low angles and minimize cosine response errors. The cosine error for
typical applications is less than 2%.
Temperature response
The temperature response is less than 0.1% per degree Celsius.
temperature error is not significant in most applications.
Long-term stability
Our research indicates that the output increases approximately 1% per year
because of changes in the optical transparency of the diffusion disk. We
recommend returning the sensor for recalibration every 2 years.
Spectral Response
As shown in the graph below, quantum response by definition is from 400 to
700 nm, and gives equal emphasis to all photons in that range. The spectral
response of the Apogee sensor, as well as a typical plant response, are also
shown.
All quantum sensor models have a stan-
bolt.
dard calibration of exactly:
as
Small
We
our
Full Sunlight
(2000 μmol m s )
PPF = sensor output x conversion factor
400 mV x 5.00
Apogee Quantum
Response
7
Calibration
-2
5.00 μmol m
Use the conversion factor
(5.00 μmol m
-2
s
-1
convert the mV signal from the
sensor to photosynthetic photon
-2
-1
flux in μmol m
s
mV output by the conversion
factor to yield μmol m
Sensor Output
(400 mV)
μ
μ
-2
-1
mol m
s
= 2,000
mol m
5
This
-1
s
per mV
per mV) to
(multiply the
-2
s
-1
).
-2
-1
s