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.
Input Voltage Requirement5.5 to 24 V DCCurrent Draw1.4 mA (quiescent), 1.8 mA (active)Calibration Uncertainty± 5 %Measurement RepeatabilityLess than 1 %Long-term Drift (Non-stability)Less than 2 % per yearNon-linearityLess than 1 % (up to 4000 µmol mˉ² sˉ ¹)Response Time0.6 s, time for detector signal to reach 95 % following a step chang, fastest data tranmission rate for SDI-12 circuitry is 1 sField of View180˚Spectral Range370 to 650 nm ( wavelengths where response is greater than 50 % fo maximum)Directional (Cosine) Response± 5 % at 75˚ zenith angleTemperature ResponseLess than 0.5 % from -20 to 50 COperating Environment-20 to 60 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 mDimensions30.5 mm diameter, 37 mm heightMass (with 5 m of cable)140 gCable5 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 wiresWarranty4 years against defects in materials and workmanshipManufacturedMade in the USA