SQ-421X-SS SDI-12 Digital Output Quantum Sensor

The SQ-421X-SS is a digital sensor that uses SDI-12 communication protocol. The sensor is calibrated for sunlight and has a command that automatically applies the immersion effect correction factor for underwater measurements. The sensor features a rugged, self-cleaning sensor housing design, and high-quality cable terminating in pre-tinned pigtail leads for easy connection to dataloggers and controllers. Typical applications include PPFD (Photosynthetic Photon Flux Density) 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 (Photosynthetically Active Radiation)/PPFD in aquatic environments, including salt water aquariums where corals are grown.

Specification

• Input Voltage Requirement: 5.5 to 24 V DC
• Current Draw: 1.4 mA (quiescent), 1.8 mA (active)
• Calibration Uncertainty: ± 5 %
• Measurement Repeatability: Less than 1 %
• Long-term Drift (Non-stability): Less than 2 % per year
• Non-linearity: Less than 1 % (up to 2500 µmol mˉ² sˉ ¹)
• Response Time: 0.6 s, time for detector signal to reach 95 % following a step chang, fastest data tranmission rate for SDI-12 circuitry is 1 s
• Field of View: 180˚
• Spectral Range: 370 to 650 nm ( wavelengths where response is greater than 50 % fo maximum)
• Directional (Cosine): Response ± 5 % at 75˚ zenith angle
• Temperature Response: Less than 0.5 % from -20 to 50 C
• Operating Environment: -20 to 60 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 (with 5 m of cable): 140 g
• Cable: 5 m of two conductor, shielded, twisted-pair wire, additional cable available in multiples of 5 m; TPR jacket (high water resistance, high UV stability, flexibility in cold conditions); pigtail lead wires
• Warranty: 4 years against defects in materials and workmanship
• Manufactured: Assembled in the USA