The S2-441-SS PAR-FAR sensor is a unique two-channel digital sensor for measuring both the PAR (PPFD) and Far-red outputs of electric grow lights 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 of PAR-FAR sensors include measuring both the traditional PPFD photosynthetic photon flux and separately quantifying the photon flux of far-red photons (700-760 nm). The outputs include the traditional quantum flux, the far-red photon flux, and the far-red fraction (far-red photon flux density / sum of PPFD and far-red photon flux density). This sensor quantifies far-red photons, and for many applications it reduces the need for a more complex measurement with a spectroradiometer.
Power Supply： 5.5 to 24 V DC
Current Draw： 1.4 mA (quiescent), 1.8 mA (active)
Calibration Factor (reciprocal of sensitivity)： Custom for each sensor and stored in firmware
Calibration Uncertainty： ± 5 %
Output Range： SDI-12
Measurement Repeatability： Less than 1 %
Long-term Drift： Less than 2 % per year
Non-linearity： Less than 1 % (up to 4000 µmol m⁻² s⁻¹) (PAR); Less than 1 % (up to 1000 µmol m⁻² s⁻¹) (Far-Red)
Response Time： Less than 0.6 s
Field of View： 180˚
Spectral Ranges： 389 to 692 nm ± 5 nm (PAR); 702 to 761 nm ± 5 (Far-Red)
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
