SQ-522-SS Modbus Digital Output Full-spectrum Quantum Sensor

The SQ-522-SS sensor outputs a digital signal using Modbus RTU protocol over RS-232 or RS-485. The sensor incorporates a rugged, self-cleaning sensor housing design, anodized aluminum body with acrylic diffuser, and high-quality cable terminating in pre-tinned pigtail leads for easy connection to dataloggers and controllers. Typical applications include PPFD measurement over plant canopies in outdoor environments, greenhouses, and growth chambers, and reflected or under-canopy (transmitted) PPFD measurements in the same environments. Quantum sensors are also used to measure PAR/PPFD in aquatic environments, including salt water aquariums where corals are grown.

How is the SQ-522 different from previous Apogee quantum sensors?
The SQ-522 is a full spectrum quantum sensor with a spectral range of 389 to 692 nm ± 5 nm, which can be seen in the graph below. This improved spectral response increases the accuracy of LED measurements.

Where is the SQ-522 used?
The SQ-522 is used to measure incoming PPFD measurements in outdoor environments, greenhouses, growth chambers, and aquariums.

SPECIFICATIONS

• Input Voltage: Requirement 5.5 to 24 V DC
• Average Max: Current Draw RS-232 37 mA; RS-485 quiescent 37 mA, active 42 mA
• Calibration: Uncertainty ± 5 %
• Measurement Repeatability: Less than 1 %
• Long-term Drift: Less than 2 % per year
• Non-linearity: Less than 1% (up to 4000 µmol mˉ² sˉ ¹)
• Spectral Range: 389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)
• Spectral Selectivity: Less than 10 % from 412 to 682 nm ± 5 nm Directional (cosine): Response ± 2 % at 45˚, ± 5 % at 75˚ zenith angle Temperature Response: -0.11 ± 0.04 % per C
• Operating Environment: -40 to 70 C, 0 to 100 % relative humidity, can be submerged in water up to depths of 30 m
• Dimensions: 30.5 mm diameter, 37 mm height
• Mass (5 m of cable): 140 g
• Cable: 5 m of two conductor, shielded, twisted-pair wire; TPR jacket; pigtail lead wires; stainless steel (316), M8 connector
• Warranty: 4 years against defects in materials and workmanship
• Manufactured: Assembled in the USA