Apogee SQ-420 User manual
APOGEE INSTRUMENTS, INC. | 721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA
TEL: (435) 792-4700 | FAX: (435) 787-8268 | WEB: APOGEEINSTRUMENTS.COM
Copyright © 2019 Apogee Instrument, Inc.
OWNER’S MANUAL
USB QUANTUM SENSOR
Model SQ-420
TABLE OF CONTENTS
Owner’s Manual ............................................................................................................................................................................... 1
Certificate of Compliance............................................................................................................................................................. 3
Introduction.................................................................................................................................................................................. 4
Sensor Models.............................................................................................................................................................................. 5
Specifications................................................................................................................................................................................ 6
Deployment and Installation ........................................................................................................................................................ 9
Software Installation .................................................................................................................................................................. 10
Operation and Measurement..................................................................................................................................................... 11
Windows Software ..................................................................................................................................................................... 13
Mac Software ............................................................................................................................................................................. 18
Maintenance and Recalibration ................................................................................................................................................. 24
Troubleshooting and Customer Support .................................................................................................................................... 26
Return and Warranty Policy ....................................................................................................................................................... 27
CERTIFICATE OF COMPLIANCE
EU Declaration of Conformity
This declaration of conformity is issued under the sole responsibility of the manufacturer:
Apogee Instruments, Inc.
721 W 1800 N
Logan, Utah 84321
USA
for the following product(s):
Models: SQ-420
Type: Quantum Sensor
The object of the declaration described above is in conformity with the relevant Union harmonization legislation:
2014/30/EU Electromagnetic Compatibility (EMC) Directive
2011/65/EU Restriction of Hazardous Substances (RoHS 2) Directive
2015/863/EU Amending Annex II to Directive 2011/65/EU (RoHS 3)
Standards referenced during compliance assessment:
EN 61326-1:2013 Electrical equipment for measurement, control and laboratory use –EMC requirements
EN 50581:2012 Technical documentation for the assessment of electrical and electronic products with respect to
the restriction of hazardous substances
Please be advised that based on the information available to us from our raw material suppliers, the products
manufactured by us do not contain, as intentional additives, any of the restricted materials including lead (see
note below), mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), polybrominated
diphenyls (PBDE), bis(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), and
diisobutyl phthalate (DIBP). However, please note that articles containing greater than 0.1% lead concentration are
RoHS 3 compliant using exemption 6c.
Further note that Apogee Instruments does not specifically run any analysis on our raw materials or end products
for the presence of these substances, but rely on the information provided to us by our material suppliers.
Signed for and on behalf of:
Apogee Instruments, October 2019
Bruce Bugbee
President
Apogee Instruments, Inc.
INTRODUCTION
Radiation that drives photosynthesis is called photosynthetically active radiation (PAR) and is typically defined as
total radiation between 400 and 700 nm. PAR is often expressed as photosynthetic photon flux density (PPFD):
photon flux in units of micromoles per square meter per second (µmol m-2 s-1, equal to microEinsteins per square
meter per second) summed from 400 to 700 nm (total number of photons from 400 to 700 nm). While Einsteins
and micromoles are equal (one Einstein = one mole of photons), the Einstein is not an SI unit, so expressing PPFD
as µmol m-2 s-1 is preferred.
The acronym PPF is also widely used and refers to the photosynthetic photon flux. The acronyms PPF and PPFD
refer to the same parameter. The two terms have co-evolved because there is not a universal definition of the
term “flux”. Some physicists define flux as per unit area per unit time. Others define flux only as per unit time.
We have used PPFD in this manual because we feel that it is better to be more complete and possibly redundant.
Sensors that measure PPFD are often called quantum sensors. A quantum is the minimum quantity of radiation
(one photon), necessary to cause a physical, electrical, or chemical reaction (e.g., absorption by photosynthetic
pigments). So one photon is a single quantum of radiation.
Apogee Instruments Quantum Sensor consists of a cast acrylic diffuser (filter), photodiode, and signal processing
circuitry mounted in an anodized aluminum housing, and a cable to connect the sensor to a measurement device.
The sensor is potted solid with no internal air space. It is designed for continuous PPFD measurement in indoor,
outdoor and underwater environments. The SQ-420 sensor output increases linearly with PPFD under sunlight
(natural setting) or electric lights (electric setting). The signal from the sensor is directly proportional to radiation
incident on a flat surface where the radiation comes from all angles of a hemisphere.
SENSOR MODELS
This manual covers the USB quantum sensor model SQ-420. Additional models are covered in their respective
manuals.
Model
Signal
Calibration
SQ-420
USB
Sunlight and Electric
light
SQ-110
Self-powered
Sunlight
SQ-120
Self-powered
Electric light
SQ-212
0-2.5 V
Sunlight
SQ-222
0-2.5 V
Electric light
SQ-214
4-20 mA
Sunlight
SQ-224
4-20 mA
Electric light
SQ-215
0-5 V
Sunlight
SQ-225
0-5 V
Electric light
SQ-311
Self-powered
Sunlight
SQ-321
Self-powered
Electric light
SQ-313
Self-powered
Sunlight
SQ-323
Self-powered
Electric light
SQ-316
Self-powered
Sunlight
SQ-326
Self-powered
Electric light
SQ-421
SDI-12
Sunlight and Electric
light
SQ-422
Modbus
Sunlight and Electric
light
Sensor model number and serial number are
located near USB connector. If you need the
manufacturing date of your sensor, please
contact Apogee Instruments with the serial
number of your sensor.
SPECIFICATIONS
Calibration Traceability
Apogee SQ series quantum sensors are calibrated through side-by-side comparison to the mean of transfer
standard quantum sensors under a reference lamp. The reference quantum sensors are recalibrated with a 200 W
quartz halogen lamp traceable to the National Institute of Standards and Technology (NIST).
SQ-420
Resolution
0.1 µmol m-2 s-1
Calibration Factor
Custom for each sensor and stored in the firmware
Calibration Uncertainty
± 5 % (see calibration Traceability below)
Measurement
Repeatability
Less than 0.5 %
Long-term Drift
(Non-stability)
Less than 2 % per year
Non-linearity
Less than 1 % (up to 4000 µmol m-2 s-1)
Response Time
Software updates every second
Field of View
180°
Spectral Range
410 to 655 nm (wavelengths where response is greater than 50 % of
maximum; see Spectral Response below)
Spectral Selectivity
Less than 10 % from 469 to 655 nm
Directional (Cosine)
Response
± 5 % at 75° zenith angle (see Cosine Response below)
Temperature Response
0.06 ± 0.06 % per C (see Temperature Response below)
Operating Environment
-40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to
depths of 30 m
Dimensions
24 mm diameter, 33 mm height
Mass
Sensor head weighs 90 g
USB Cable
4.5 m (15 ft)
Current Draw (when
Logging)
61 mA
Spectral Response
Temperature Response
Mean spectral response of six sensors
(error bars represent two standard
deviations above and below mean)
compared to PAR (PPFD) weighting
function. Spectral response
measurements were made at 10 nm
increments across a wavelength range of
300 to 800 nm in a monochromator with
an attached electric light source.
Measured spectral data from each
quantum sensor were normalized by the
measured spectral response of the
monochromator/electric light
combination, which was measured with a
spectroradiometer.
Mean temperature response of eight
replicate sensors (errors bars represent
two standard deviations above and
below mean). Temperature response
measurements were made at 10 C
intervals across a temperature range of -
10 to 40 C in a temperature controlled
chamber under a fixed, broad spectrum,
electric lamp. At each temperature set
point, a spectroradiometer was used to
measure light intensity from the lamp
and all quantum sensors were compared
to the spectroradiometer. The
spectroradiometer was mounted external
to the temperature control chamber and
remained at room temperature during
the measurements.
Cosine Response
Directional, or cosine, response is defined as the
measurement error at a specific angle of radiation
incidence. Error for Apogee SQ series quantum
sensors is approximately ± 2 % and ± 5 % at solar
zenith angles of 45° and 75°, respectively.
Mean cosine response of twenty-
three replicate sensors (error bars
represent two standard deviations
above and below mean). Cosine
response measurements were
made by direct side-by-side
comparison to the mean of four
reference thermopile
pyranometers, with solar zenith
angle-dependent factors applied to
convert total shortwave radiation
to PPFD. Blue points represent the
AM response and red points
represent the PM response.
DEPLOYMENT AND INSTALLATION
Mount the sensor to a solid surface with the nylon mounting screw provided. To accurately measure PPFD incident
on a horizontal surface, the sensor must be level. An Apogee Instruments model AL-100 Leveling Plate is
recommended to level the sensor when used on a flat surface or being mounted to surfaces such as wood. To
facilitate mounting on a mast or pipe, the Apogee Instruments model AL-120 Solar Mounting Bracket with Leveling
Plate is recommended.
To minimize azimuth error, the sensor should be mounted with the cable pointing toward true north in the
northern hemisphere or true south in the southern hemisphere. Azimuth error is typically less than 1 %, but it is
easy to minimize by proper cable orientation.
In addition to orienting the cable to point toward the nearest pole, the sensor should also be mounted such that
obstructions (e.g., weather station tripod/tower or other instrumentation) do not shade the sensor. Once
mounted, the green cap should be removed from the sensor. The green cap can be used as a protective covering
for the sensor when it is not in use.
Nylon Screw: 10-32x3/8
Model AL-100
Nylon Screw: 10-32x3/8
Model AL-120
SOFTWARE INSTALLATION
The most recent version of ApogeeConnect software can be downloaded at
http://www.apogeeinstruments.com/downloads/.
Installing the software on a PC (Windows compatible, XP and later)
1. Double click on the installer package
2. On the ‘Welcome’ screen, please click ‘Next’ to continue.
3. Select the radio button next to “I Agree” to the UELA… and click ‘Next’ to continue.
4. On the ‘Ready to Install the Program’ screen, click ‘Install’ to continue.
5. Click ‘Finish’ to complete the installation. There are shortcuts on your desktop and in your start bar.
Installing the software on a Mac (Mac compatible, 10.10 and later)
1. Double click on the installer package
2. On the ‘Introduction’ screen, please click ‘Continue’ to proceed.
3. Select ‘Continue’ on the ‘Read Me’ screen to continue, this screen contains a history of updates made to
the ApogeeConnect software versions.
4. Select ‘Continue’ on the ‘License’ screen to receive a prompt to agree to the terms of the software license
agreement. Click ‘Agree’ to continue once you receive the prompt.
5. On the ‘Installation Type’ screen, click ‘Install’ to install the software. You can change the location the
software installs to by clicking ‘Change Install Location…’. *Note: You may be prompted for an
administrator password at this time. If you are, proceed by entering your respective password and clicking
‘Install Software’.
6. Once you receive the message “The installation was successful.” on the ‘Summary’ screen click ‘Close’.
Your software is now ready to be used.
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