Apogee Instruments SQ-212 User manual

APOGEE INSTRUMENTS, INC. | 721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA
TEL: [phone] | FAX: [phone] | WEB: APOGEEINSTRUMENTS.COM
Copyright © 2020 Apogee Instruments, Inc.
OWNER’S MANUAL
QUANTUM SENSOR
Model SQ-212, SQ-222, SQ-215, and SQ-225
(including SS models, formerly smaller)

Owner’s Manual ............................................................................................................................................................................... 1
Certificate of Compliance......................................................................................................................................................... 3
Introduction ............................................................................................................................................................................. 4
Sensor Models ......................................................................................................................................................................... 5
Specifications ........................................................................................................................................................................... 6
Deployment and Installation.................................................................................................................................................... 9
Cable Connectors................................................................................................................................................................... 10
Operation and Measurement ................................................................................................................................................ 11
Maintenance and Recalibration............................................................................................................................................. 17
Troubleshooting and Customer Support................................................................................................................................ 19
Return and Warranty Policy................................................................................................................................................... 21

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-212, SQ-222, SQ-215, SQ-225
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, August 2020
Bruce Bugbee
President
Apogee Instruments, Inc.

INTRODUCTION
Radiation that drives photosynthesis is called photosynthetically active radiation (PAR) and is typically defined as
total radiation across a range of 400 to 700 nm. PAR is almost universally quantified as photosynthetic photon flux
density (PPFD), the sum of photons from 400 to 700 nm in units of micromoles per square meter per second (µmol
m-2 s-1, equal to microEinsteins m-2 s-1). While microEinsteins 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. Daily total PPFD is typically
reported in units of moles of photons per square meter per day (mol m-2 d-1) and is often called daily light integral
(DLI).
The acronym PPF is also used and refers to the photosynthetic photon flux. The acronyms PPF and PPFD refer to
the same variable. Both terms are used because there is not a universal definition of the term flux. Flux is
sometimes defined as per unit area per unit time and sometimes defined as per unit time only. PPFD is used in this
manual.
Sensors that measure PPFD are often called quantum sensors due to the quantized nature of radiation. A quantum
refers to the minimum quantity of radiation, one photon, involved in physical interactions (e.g., absorption by
photosynthetic pigments). In other words, one photon is a single quantum of radiation.
Typical applications of quantum sensors include measurement of incident PPFD on plant canopies in outdoor
environments or in greenhouses and growth chambers, and reflected or under-canopy (transmitted) PPFD
measurement in the same environments.
Apogee Instruments SQ series quantum sensors consist 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. Sensors are potted solid with no internal air space, and are designed for continuous PPFD
measurement in indoor or outdoor environments. SQ series sensors output an analog voltage that is directly
proportional to PPFD under sunlight (e.g., model SQ-215) or electric lights (e.g., model SQ-225). The voltage signal
from the sensor is directly proportional to radiation incident on a planar surface (does not have to be horizontal),
where the radiation emanates from all angles of a hemisphere.

SENSOR MODELS
This manual covers quantum sensor models SQ-212/SQ/222 and SQ-215/SQ-225, which provide a voltage signal.
Additional models are covered in their respective manuals.
Model
Signal
Calibration
SQ-212
0-2.5 V
Sunlight
SQ-222
0-2.5 V
Electric light
SQ-215
0-5 V
Sunlight
SQ-225
0-5 V
Electric light
SQ-110
Self-powered
Sunlight
SQ-120
Self-powered
Electric light
SQ-214
4-20 mA
Sunlight
SQ-224
4-20 mA
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-420
USB
Sunlight and Electric light
SQ-421
SDI-12
Sunlight and Electric light
SQ-422
Modbus
Sunlight and Electric light
Serial Number 0-10573 (SQ-212), 0-10273 (SQ-
222), 0-10433 (SQ-215), 0-10533 (SQ-225) Sensor
model number and serial number are located
near the pigtail leads on the sensor cable. If you
need the manufacturing date of your sensor,
please contact Apogee Instruments with the
serial number of your sensor.
Serial Numbers 10574 (SQ-212), 10274 (SQ-
222), 10434 (SQ-215), 10534 (SQ-225) and
above: Sensor model number and serial number
are located on the bottom of the sensor. If you
need the manufacturing date of your sensor,
please contact Apogee Instruments with the
serial number of your sensor.

SPECIFICATIONS
SQ-212/SQ-222-SS
SQ-215/SQ-225-SS
Power Supply
3.3 to 24 V DC; nominal current draw 300 µA
5.5 to 24 V DC**; nominal current draw 300 µA
**Sensors with a serial number smaller than 3762 should
not be powered with more than 5 V DC
Sensitivity
Serial # 8382 and above
0.6 mV per µmol m-2 s-1
1.25 mV per µmol m-2 s-1
Sensitivity
Serial # 0-8381
1 mV per µmol m-2 s-1
2 mV per µmol m-2 s-1
Calibration Factor
Serial # 8382 and above
1.6 µmol m-2 s-1 per mV
0.8 µmol m-2 s-1 per mV
Calibration Factor
Serial # 0-8381
1µmol m-2 s-1 per mV
0.5 µmol m-2 s-1 per mV
Calibrated Output Range
0 to 2.5 V
0 to 5 V
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
Serial # 8382 and above
Less than 1 % (up to 4000 µmol m-2 s-1;
maximum PPFD measurement is 4000 µmol m-2 s-1)
Non-linearity
Serial # 0-8381
Less than 1 % (up to 2500 µmol m-2 s-1;
maximum PPFD measurement is 2500 µmol m-2 s-1)
Response Time
Less than 1 ms
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
Serial # 10574 (SQ-212), 10274
(SQ-222), 10434 (SQ-215),
10534 (SQ-225) and above
30.5 mm diameter, 37 mm height
Dimensions
Serial # 0-10573 (SQ-212), 0-
10273 (SQ-222), 0-10433 (SQ-
215), 0-10533 (SQ-225)
24 mm diameter, 33 mm height
Mass (with 5 m cable)
Serial # 10574 (SQ-212), 10274
(SQ-222), 10434 (SQ-215),
10534 (SQ-225) and above
140 g
Mass (with 5 m cable)
Serial # 0-10573 (SQ-212), 0-
10273 (SQ-222), 0-10433 (SQ-
215), 0-10533 (SQ-225)
100 g
Cable
5 m of two conductor, shielded, twisted-pair wire; TPR jacket (high water resistance, high UV
stability, flexibility in cold conditions); pigtail lead wires; stainless steel (316), M8 connector

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).
Spectral Response
Temperature Response
Mean temperature response of eight
SQ-100 series quantum 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
approximately -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
experiment.
Mean spectral response of six SQ-100
series quantum sensors (error bars
represent two standard deviations
above and below mean) compared to
defined plant response to photons.
Spectral response measurements were
made at 10 nm increments across a
wavelength range of 300 to 800 nm with a
monochromator and 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.

Cosine Response
Mean directional (cosine) response of six
apogee SQ-100 series quantum sensors.
Directional response measurements
were made on the rooftop of the
Apogee building in Logan, Utah.
Directional response was calculated as
the relative difference of SQ-500
quantum sensors from the mean of
replicate reference quantum sensors (LI-
COR models LI-190 and LI-190R, Kipp &
Zonen model PQS 1). Data were also
collected in the laboratory using a
reference lamp and positioning the
sensor at varying angles.
Directional (cosine) response is defined as the
measurement error at a specific angle of
radiation incidence. Error for Apogee SQ-100
series quantum sensors is approximately ± 2 %
and ± 5 % at solar zenith angles of 45° and 75°,
respectively.

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
Nylon Screw: 10-32x3/8
Model AL-100
Model AL-120
Important: Only use the nylon screw provided
when mounting to insulate the non-anodized
threads of the aluminum sensor head from the
base to help prevent galvanic corrosion. For
extended submersion applications, more insulation
may be necessary. Contact Apogee tech support for
details.

CABLE CONNECTORS
Apogee started offering cable connectors on some
bare-lead sensors in March 2018 to simplify the
process of removing sensors from weather stations
for calibration (the entire cable does not have to be
removed from the station and shipped with the
sensor).
The ruggedized M8 connectors are rated IP68, made
of corrosion-resistant marine-grade stainless-steel,
and designed for extended use in harsh
environmental conditions.
Cable connectors are attached directly to the head.
Instructions
Pins and Wiring Colors: All Apogee connectors have
six pins, but not all pins are used for every sensor.
There may also be unused wire colors inside the cable.
To simplify connection to a measurement device, the
unused pigtail lead wire colors are removed.
If a replacement cable is required, please contact
Apogee directly to ensure ordering the proper pigtail
configuration.
Alignment: When reconnecting a sensor, arrows on
the connector jacket and an aligning notch ensure
proper orientation.
Disconnection for extended periods: When
disconnecting the sensor for an extended period of
time from a station, protect the remaining half of the
connector still on the station from water and dirt with
electrical tape or other method.
A reference notch inside the connector ensures
proper alignment before tightening.
When sending sensors in for calibration, only send the
sensor head.
Tightening: Connectors are designed to be firmly
finger-tightened only. There is an o-ring inside the
connector that can be overly compressed if a wrench is
used. Pay attention to thread alignment to avoid cross-
threading. When fully tightened, 1-2 threads may still
be visible.
WARNING: Do not tighten the connector by twisting
the black cable or sensor head, only twist the metal
connector (yellow arrows).
Finger-tighten firmly