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S2-131 Red - Far-Red Sensor

Updated:2025-03-13

Brand: APOGEE
Model: S2-131
Description: The S2-131 Red - Far-red sensor is a two-channel self-powered sensor. The sensor features a rugged, aluminum housing that is fully-submersible and built to withstand harsh conditions, and high-quality
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Product Details

S2-131 Red - Far-Red Sensor Introduction：

Specification Sheet

The S2-13 Red - Far-red sensor is a two-channel self-powered sensor. 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.

The analog version of this sensor (S2-131) comes with the inline cable connector placed 30 cm from the sensor head for either standard use as a long-cable pigtail sensor, or for use with our microCache Bluetooth Micro Logger by unscrewing the connector, discarding the long section of cable and then screwing the sensor to the mating connector on the microCache.

S2-131 Red - Far-Red Sensor drawing：

S2-131 Red - Far-Red Sensor Specifications:

Power Supply	Self-powered
Output (sensitivity)	0.08 mV per μmol mˉ2 sˉ1 (typical value, variable from sensor to sensor)
Calibration Factor (recipricol of sensitivity)	12 μmol mˉ2 sˉ1 per mV (typical value, variable from sensor to sensor)
Calibration Uncertainty	± 5 %
Output Range	0 to 33 mV
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 1 ms
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