Two-channel sensor for 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.
This sensor is a research-grade, cost-effective two-channel sensor for monitoring plant light environments, including calculation of the red to far-red ratio (red photon flux density / far-red photon flux density) and far-red fraction (far-red photon flux density / sum of red and far-red photon flux densities).
The red – far-red sensor has a spectral range of 645 to 665 nm ± 5 nm (red) and 720 to 740 nm ± 5 nm (far-red). The spectral responses can be seen in the graph below.
Rugged, Self-cleaning Housing
The patented domed shaped sensor head (diffuser and body) facilitates runoff of dew and rain to keep the sensor clean and minimizes errors caused by dust blocking the radiation path. Sensors are housed in a rugged, anodized aluminum body and electronics are fully-potted.
Applications include monitoring plant light environments, researching plant morphogenic activity, and photobiology studies.
The AL-120 Solar Mounting Bracket with Leveling Plate facilitates mounting the sensor to a mast or pipe. The AL-100 Solar Sensor Leveling Plate is designed to level the sensor while sitting on a flat surface or mounting to a surface.
Available in digital SDI-12 output or with an analog output.
High Quality Cable
Pigtail-lead sensors feature an IP68, marine-grade stainless-steel cable connectors built directly into the sensor head to simplify sensor removal for maintenance and recalibration. Cable is shielded-twisted-pair wire with a TPR jacket for high water resistance, UV stability, and flexibility in cold conditions.
|S2-131-SS(Analog Sensor)||S2-431-SS(SDI-12 Sensor)|
|Power Supply||Self-powered||5.5 to 24 V DC|
|Current Draw||–||1.4 mA (quiescent), 1.8 mA (active)|
|Output (Sensitivity)||0.01 mV per µmol m-2 s-1 (Red and Far-Red)||–|
|Calibration Factor (reciprocal of sensitivity)||100 µmol m-2 s-1 per mv (Red and Far-Red)||Custom for each sensor and stored in firmware|
|Calibration Uncertainty||± 5 %||± 5 %|
|Output Range||0 to 4 mV (Red and Far-Red)||SDI-12|
|Wavelength Ranges||645 to 665 nm ± 5 nm (Red)
720 to 740 nm ± 5 nm (Far-Red)
|645 to 665 nm ± 5 nm (Red)
720 to 740 nm ± 5 nm (Far-Red)
|Measurement Range||0 to 400 µmol m-2 s-1 (Red and Far-Red)||0 to 400 µmol m-2 s-1 (Red and Far-Red)|
|Measurement Repeatability||Less than 1 %||Less than 1 %|
|Long-term Drift||Less than 2 % per year||Less than 2 % per year|
|Response Time||Less than 1 ms||Less than 0.6 s|
|Non-linearity||Less than 1 % (up to 4000 µmol m-2 s-1)||Less than 1 % (up to 4000 µmol m-2 s-1)|
|Field of View||180°||180°|
|Directional (Cosine) Response||± 2 % at 45°; ± 5 % at 75° zenith angle||± 2 % at 45°; ± 5 % at 75° zenith angle|
|Temperature Response||Less than 0.1 % per C||Less than 0.1 % per C|
|Housing||Anodized aluminum body with acrylic diffuser||Anodized aluminum body with acrylic diffuser|
|Operating Environment||-40 to 70 C; 0 to 100 % relative humidity||-40 to 70 C; 0 to 100 % relative humidity|
|Dimensions||30.5 mm diameter, 37 mm height||30.5 mm diameter, 37 mm height|
|Mass (with 5 m of cable)||140 g||140 g|
|Cable||5 m of shielded, twisted-pair wire with TPR jacket and stainless steel connector||5 m of shielded, twisted-pair wire with TPR jacket and stainless steel connector|
|Warranty||4 years against defects in materials and workmanship||4 years against defects in materials and workmanship|
Warranty and Support
All Apogee products are backed by an industry-leading four year warranty and outstanding customer support