OWNER’S MANUAL QUANTUM SENSOR Models SQ-214 and SQ-224 (including SS models) 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 Instruments, Inc.
TABLE OF CONTENTS Owner’s Manual ............................................................................................................................................................................... 1 Certificate of Compliance ......................................................................................................................................................... 3 Introduction ..........................................................................................................
CERTIFICATE OF COMPLIANCE EU Declaration of Conformity This declaration of conformity is issued under the sole responsibility of the manufacturer: 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 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).
SENSOR MODELS This manual covers quantum sensor models SQ-214/SQ-224 that provide a current output. Additional models are covered in their respective manuals. 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.
SPECIFICATIONS Power Supply Sensitivity Calibration Factor SQ-214/SQ-224-SS 7 to 24 V DC with a maximum current draw 22 mA (2 mA quiescent current draw) 0.
Spectral Response Mean spectral response of six SQ series quantum sensors (error bars represent two standard deviations above and below mean) compared to 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.
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 twentythree SQ series quantum sensors (error bars represent two standard deviations above and below mean).
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.
CABLE CONNECTORS Apogee started offering in-line 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.
OPERATION AND MEASUREMENT Connect the sensor to a measurement device (meter, datalogger, controller) capable of measuring and displaying a 4-20 mA signal. In order to maximize measurement resolution and signal-to-noise ratio, the input range of the measurement device should closely match the output range of the quantum sensor. DO NOT connect the sensor to a power source greater than 24 V DC.
Sensor Calibration Apogee SQ-214, SQ-224 models have a standard PPFD calibration factor of exactly: 250.0 µmol m-2 s-1 per mA with a 4 mA offset Multiply this calibration factor by the difference of the measured mA signal and the 4.0 mA offset to convert sensor output to PPFD in units of µmol m-2 s-1: Calibration Factor (250 µmol m-2 s-1 per mA) * [Sensor Output Signal (mA) – Offset (4.0 mA)] = PPFD (µmol m-2 s-1) 250 * (12.0 – 4) = 2000 Full Sunlight (2000 µmol m-2 s-1) Sensor Output 12.
Spectral Errors and Yield Photon Flux Measurements Apogee quantum sensors are calibrated to measure PPFD for either sunlight or electric light. The difference between the calibrations is 12 %. A sensor calibrated for electric lights (calibration source is T5 cool white fluorescent lamps) will read approximately 12 % low in sunlight.
Spectral Errors for PPFD and YPFD Measurements with Apogee SQ Series Quantum Sensors Radiation Source (Error Calculated Relative to Sun, Clear Sky) Sun (Clear Sky) Sun (Cloudy Sky) Reflected from Grass Canopy Reflected from Deciduous Canopy Reflected from Conifer Canopy Transmitted below Grass Canopy Transmitted below Deciduous Canopy Transmitted below Conifer Canopy Radiation Source (Error Calculated Relative to Cool White Fluorescent, T5) Cool White Fluorescent (T5) Cool White Fluorescent (T8) Cool White
MAINTENANCE AND RECALIBRATION Moisture or debris on the diffuser is a common cause of low readings. The sensor has a domed diffuser and housing for improved self-cleaning from rainfall, but materials can accumulate on the diffuser (e.g., dust during periods of low rainfall, salt deposits from evaporation of sea spray or sprinkler irrigation water) and partially block the optical path. Dust or organic deposits are best removed using water or window cleaner and a soft cloth or cotton swab.
Homepage of the Clear Sky Calculator. Two calculators are available: one for quantum sensors (PPFD) and one for pyranometers (total shortwave radiation). Clear Sky Calculator for quantum sensors. Site data are input in blue cells in middle of page and an estimate of PPFD is returned on right-hand side of page.
TROUBLESHOOTING AND CUSTOMER SUPPORT Independent Verification of Functionality Apogee models SQ-214 and SQ-224 quantum sensors provide a 4-20 mA output that is proportional to incident PPFD. A quick and easy check of sensor functionality can be determined using a DC power supply and an ammeter. Power the sensor with a DC voltage by connecting the positive voltage signal to the red wire from the sensor and the negative (or common) to the black wire from the sensor.
RETURN AND WARRANTY POLICY RETURN POLICY Apogee Instruments will accept returns within 30 days of purchase as long as the product is in new condition (to be determined by Apogee). Returns are subject to a 10 % restocking fee. WARRANTY POLICY What is Covered All products manufactured by Apogee Instruments are warranted to be free from defects in materials and craftsmanship for a period of four (4) years from the date of shipment from our factory.
Authorization (RMA) number from our technical support department by calling (435) 245-8012 or by submitting an online RMA form at www.apogeeinstruments.com/tech-support-recalibration-repairs/. We will use your RMA number for tracking of the service item. 2. Send all RMA sensors and meters back in the following condition: Clean the sensor’s exterior and cord. Do not modify the sensors or wires, including splicing, cutting wire leads, etc.
