The S2-431-SS Red - Far-red sensor is a two-channel digital sensor with SDI-12 communication protocol. The sensor features a rugged, aluminum housing that is fully-submersible and built to withstand harsh conditions. The sensor cable includes an IP68 marine-grade stainless-steel cable connector to simplify sensor removal and replacement from permanent installations for maintenance and calibration. Typical applications include measuring the Red / Far-red ratio (RFR) for ecological applications, including the effect of spectral quality on phytochrome. The RF ratio influences plant height, leaf expansion rates, and other photobiology and plant morphogenic responses.
Power Supply： 5.5 to 24 V DC
Current Draw： 1.4 mA (quiescent), 1.8 mA (active)
Calibration Factor： Custom for each sensor and stored in firmware
Calibration Uncertainty： ± 5 %
Output Range： SDI-12
Wavelength Ranges： 645 to 665 nm ± 5 nm (Red); 720 to 740 nm ± 5 nm (Far-Red)
Measurement Range： 0 to 400 µmol mˉ² sˉ¹ (Red and Far-Red)
Measurement Repeatability： Less than 1 %
Long-term Drift： Less than 2 % per year
Response Time： Less than 0.6 s
Non-linearity： Less than 1 % (up to 400 µmol mˉ² sˉ¹) (Red and Far-Red)
Field of View： 180°
Directional (Cosine) Response： ± 2 % at 45˚, ± 5 % at 75˚ zenith angle
Temperature Response： Less than 0.1 % per C
Housing： Anodized aluminum body with acrylic diffuser
IP Rating： IP68
Operating Environment： -40 to 70 C; 0 to 100 % relative humidity
Dimensions： 30.5 mm diameter, 37 mm height
Mass (with 5 m of cable)： 140 g
Cable： 5 m of shielded, twisted-pair wire; TPR jacket (high water resistance, high UV stability, flexibility in cold conditions); pigtail lead wires; stainless steel (316), M8 connector
Warranty： 4 years against defects in materials and workmanship
