The SQ-500 is a self-powered, analog full-spectrum quantum sensor with a 0 to 40 mV output. The sensor incorporates a blue-enhanced silicon photodiode and custom optical filters with a rugged, self-cleaning sensor housing design, anodized aluminum body with acrylic diffuser. 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. Sensor includes IP67 marine-grade stainless-steel cable connector 30 cm from head to simplify sensor removal and replacement for maintenance and recalibration.
How is the SQ-500 differentfrom previous Apogee quantum sensors?
The SQ-500 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 respose increases the acuracy of LED measurements.
Where is the SQ-500 used?
The SQ-500 is used to measure incoming PPFD measurements in outdoor environments, greenhouses, growth chambers, and aquariums.
Power Supply Self-powered
Output (Sensitivity) 0.01 mV per µmol mˉ² sˉ¹
Calibration Factor (Reciprocal of Sensitivty) 100 µmol mˉ² sˉ¹ per mV
Calibration Uncertainty ± 5 %
Calibrated Output Range 0 to 40 mV
Measurement Range 0 to 4000 µmol mˉ² sˉ¹
Measurement Repeatability Less than 0.5 %
Long-term Drift Less than 2 % per year
Non-linearity Less than 1 % (up to 4000 µmol mˉ² sˉ¹)
Response Time Less than 1 ms
Field of View 180 ˚
Spectral Range 389 to 692 nm ± 5 nm (wavelegths where response is greater than 50 % of maximum)
Spectral Selectivity Less than 10 % from 412 to 682 nm ± 5 nm
Directional (Cosine) Response ± 5 % at 75 ˚ zenith angle
Azimuth Error Less than 0.5 %
Tilt Error Less than 0.5 %
Temperature Response -0.11 ± 0.04 % Cˉ¹
Uncertainty in Daily Total Less than 5 %
Detector Blue-enhanced silicon photodiode
Housing Anodized aluminum body with acrylic diffuser
IP Rating IP68
Operating Environment -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m
Dimensions 24 mm diameter, 37 mm height
Mass 100 g (with 5 m of lead wire)
Cable 5 m of shielded, twisted-pair wire with TPR jacket (high water resistance, high UV stability, flexibility in cold conditions)
Warranty 4 years against defects in materials and workmanship
