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Related Manuals for Apogee Instruments SQ-421X
Summary of Contents for Apogee Instruments SQ-421X
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Page 1: Owner's Manual
OWNER’S MANUAL QUANTUM SENSOR Model SQ-421X Rev: 30-Mar-2022 APOGEE INSTRUMENTS, INC. | 721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA TEL: (435) 792-4700 | FAX: (435) 787-8268 | WEB: APOGEEINSTRUMENTS.COM Copyright © 2022 Apogee Instruments, Inc. -
Page 2: Table Of Contents
TABLE OF CONTENTS 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 ..............................10 Maintenance and Recalibration ............................. 18 Troubleshooting and Customer Support .......................... -
Page 3: Certificate Of Compliance
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 we rely on the information provided to us by our material suppliers. -
Page 4: Introduction
(transmitted) PPFD measurement in the same environments. Apogee Instruments SQ-421X-SS quantum sensors consist of a cast acrylic diffuser (filter), interference filter, photodiode, and signal processing circuitry mounted in an anodized aluminum housing, and a cable to connect the sensor to a measurement device. -
Page 5: Sensor Models
SENSOR MODELS This manual covers the SDI-12 communication protocol, quantum sensor model SQ-421X. Additional models are covered in their respective manuals. Model Signal SQ-421X SDI-12 SQ-100X Self-powered SQ-202X 0-2.5 V SQ-204X 4-20 mA SQ-205X 0-5 V SQ-420X SQ-422X ModBus A sensor’s model number and serial number are located on the bottom of the sensor. -
Page 6: Specifications
SPECIFICATIONS SQ-421X-SS Input Voltage 5.5 to 24 V DC Requirement Current Draw 1.4 mA (quiescent), 1.8 mA (active) Calibration Uncertainty ± 5 % (see Calibration Traceability below) Measurement Less than 1 % Repeatability Long-term Drift Less than 2 % per year... - Page 7 Spectral Response Mean spectral response of four SQ-100x series quantum sensors compared to PPFD weighting function. Spectral response measurements were made at 10 nm increments across a wavelength range of 350 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...
- Page 8 Cosine Response Directional (cosine) response is defined as the measurement error at a specific angle of radiation incidence. Error for Apogee SQ- 100x series quantum sensors is approximately ± 2 % and ± 5 % at solar zenith angles of 45° and 75°, respectively. Mean cosine response of five SQ- 100X series quantum sensors.
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Page 9: 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. -
Page 10: Cable Connectors
CABLE CONNECTORS Apogee sensors offer cable connectors 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, Cable connectors are attached directly to the head. -
Page 11: Operation And Measurement
OPERATION AND MEASUREMENT The SQ-421X quantum sensor has a SDI-12 output, where shortwave radiation is returned in digital format. Measurement of SQ-421X quantum sensors requires a measurement device with SDI-12 functionality that includes the M or C command. Wiring for SQ-421X... - Page 12 “!”. SDI-12 language supports a variety of commands. Supported commands for the Apogee Instruments SP-521 quantum sensors are listed in the following table (“a” is the sensor address. The following ASCII Characters are valid addresses: “0-9” or “A-Z”).
- Page 13 Make Measurement Command: M! The make measurement command signals a measurement sequence to be performed. Data values generated in response to this command are stored in the sensor's buffer for subsequent collection using “D” commands. Data will be retained in sensor storage until another “M”, “C”, or “V” command is executed.
- Page 14 Concurrent Measurement Command: aC! A concurrent measurement is one which occurs while other SDI-12 sensors on the bus are also making measurements. This command is similar to the “aM!” command, however, the nn field has an extra digit and the sensor does not issue a service request when it has completed the measurement.
- Page 15 Change Sensor Address: aAb! The change sensor address command allows the sensor address to be changed. If multiple SDI-12 devices are on the same bus, each device will require a unique SDI-12 address. For example, two SDI-12 sensors with the factory address of 0 requires changing the address on one of the sensors to a non-zero value in order for both sensors to communicate properly on the same channel: Command...
- Page 16 Spectral Errors Apogee SQ-100X series sensors can measure PPFD for sunlight and electric light with a single calibration factor. However, errors occur in various light sources due to changes in spectral output. If the light source spectrum is known, then errors can be estimated and used to adjust the measurements. The weighting function for PPFD is shown in the graph below, along with the spectral response of Apogee SQ-100X series quantum sensors.
- Page 17 Spectral Errors for PPFD Measurements with Apogee SQ-100X Series Quantum Sensors Radiation Source (Error Calculated Relative to Sun, Clear Sky) PPFD Error [%] 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...
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Page 18: Maintenance And Recalibration
3. Salt deposit accumulation from evaporation of sea spray or sprinkler irrigation water. Apogee Instruments upward-looking sensors have a domed diffuser and housing for improved self-cleaning from rainfall, but active cleaning may be necessary. Dust or organic deposits are best removed using water, or window cleaner, and a soft cloth or cotton swab. - Page 19 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.
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Page 20: Troubleshooting And Customer Support
TROUBLESHOOTING AND CUSTOMER SUPPORT Independent Verification of Functionality If the sensor does not communicate with the datalogger, use an ammeter to check the current draw. It should be near 1.4 mA when the sensor is not communicating and spike to approximately 1.8 mA when the sensor is communicating. -
Page 21: Return And Warranty Policy
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... - Page 22 84321, USA 5. Upon receipt, Apogee Instruments will determine the cause of failure. If the product is found to be defective in terms of operation to the published specifications due to a failure of product materials or craftsmanship, Apogee Instruments will repair or replace the items free of charge.
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