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S2-431 SDI-12 Red - Far-Red Sensor

Updated:2025-03-13

Brand: APOGEE
Model: S2-431
Description: The S2-431 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 hars
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Product Details

S2-431 SDI-12 Red - Far-Red Sensor Introduction：

Specification Sheet

The S2-431 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, and high-quality cable terminating in pre-tinned pigtail leads for easy connection to dataloggers and controllers. 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.

S2-431 SDI-12 Red - Far-Red Sensor drawing：

S2-431 SDI-12 Red - Far-Red Sensor Specifications:

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
Manufactured	Made in the USA