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Related Manuals for Apogee Instruments SQ-422X
Summary of Contents for Apogee Instruments SQ-422X
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Page 1: Owner's Manual
OWNER’S MANUAL QUANTUM SENSOR Model SQ-422X Rev: 16-Nov-2021 APOGEE INSTRUMENTS, INC. | 721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA TEL: (435) 792-4700 | FAX: (435) 787-8268 | WEB: APOGEEINSTRUMENTS.COM Copyright © 2021 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 ..............................8 Cable Connectors ................................... 10 Operation and Measurement ..............................10 Maintenance and Recalibration ............................. 19 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
Sensors are potted solid with no internal air space and are designed for continuous PPFD measurement in indoor or outdoor environments. The SQ-422X-SS model outputs a digital signal using Modbus RTU communication protocol over RS-232 or RS-485. -
Page 5: Sensor Models
SENSOR MODELS This manual covers the Modbus RTU communication protocol, quantum sensor model SQ-422X. Additional models are covered in their respective manuals. Model Signal SQ-422X Modbus SQ-100X Self-powered SQ-202X 0-2.5 V SQ-204X 4-20 mA SQ-205X 0-5 V SQ-420X SQ-421X SDI-12 A sensor’s model number and serial number... -
Page 6: Specifications
SPECIFICATIONS SQ-422X-SS Input Voltage Requirement 5.5 to 24 V DC RS-232 37 mA; Average Max Current Draw RS-485 quiescent 37, active 42 mA Calibration Uncertainty ± 5 % (see Calibration Traceability below) Measurement Repeatability Less than 1 % Long-term Drift... - 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 monochromator/electric...
- 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.
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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-422X-SS quantum sensor has a Modbus output, where photosynthetic photon flux density (PPFD) is returned in digital format. Measurement of SQ-422X quantum sensors requires a measurement device with a Modbus interface that supports the Read Holding Registers (0x03) function. - Page 12 Coefficients are programmed into the sensors at the factory. Modbus Interface The following is a brief explanation of the Modbus protocol instructions used in Apogee SQ-422X quantum sensors. For questions on the implementation of this protocol, please refer to the official serial line implementation of the Modbus protocol: http://www.modbus.org/docs/Modbus_over_serial_line_V1_02.pdf...
- Page 13 Communication Parameters: Apogee Sensors communicate using the Modbus RTU variant of the Modbus protocol. The default communication parameters are as follows: Slave address: 1 Baudrate: 19200 Data bits: 8 Stop bits: 1 Parity: Even Byte Order: Big-Endian (most significant byte sent first) The baudrate and slave address are user configurable.
- Page 14 (shifted two decimal points to the left)* running average heater status *Registers marked with an asterisk (*) cannot be written to unless a specific procedure is followed. Contact Apogee Instruments to receive the procedure for writing these registers.
- Page 15 Write only registers (function code 0x10). Integer Registers Writing to this register resets Coefficients to firmware defaults. (NOT factory calibrated values!) Slave Address = 1, Model = 522, Serial = 1000, Baud = 3, Parity = 2, Stopbits = 1, running average = 1...
- Page 16 Packet Framing: Apogee sensors use Modbus RTU packets and tend to adhere to the following pattern: Slave Address (1 byte), Function Code (1 byte), Starting Address (2 bytes), Number of Registers (2 bytes), Data Length (1 byte, optional) Data (n bytes, optional) Modbus RTU packets use the zero-based address when addressing registers.
- Page 17 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 18 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 19: Maintenance And Recalibration
3. Salt deposit accumulation from evaporation of sea spray or sprinkler irrigation water. Apogee Instruments quantum 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 20 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 21: 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 drain. It should be near 37 mA when the sensor is powered. Any current drain significantly greater than approximately 37 mA indicates a problem with power supply to the sensors, wiring of the sensor, or sensor electronics. -
Page 22: 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 23 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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