S2-141-SS PAR-FAR Sensor

The S2-141-SS PAR-FAR sensor is a unique two-channel sensor for measuring both the PAR (PPFD) and Far-red outputs of electric grow lights and is self-powered. The sensor features a rugged, alumin

  • Product Name:S2-141-SS PAR-FAR Sensor
  • Item No.:S2-141-SS
  • Manufacturers:Apogee
  • Country of Origin:USA

The S2-141-SS PAR-FAR sensor is a unique two-channel sensor for measuring both the PAR (PPFD) and Far-red outputs of electric grow lights and is self-powered. 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.

The analog version of this sensor (S2-141) 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.


Power Supply:    Self-powered

Output (sensitivity):     0.01 mV per µmol m⁻² s⁻¹ (PAR); 0.02 mV per µmol m⁻² s⁻¹ (Far-Red)

Calibration Factor (reciprocal of sensitivity):     100 µmol m⁻² s⁻¹ per mV (PAR); 50 µmol m⁻² s⁻¹ per mV (Far-Red)

Calibration Uncertainty:     ± 5 %

Output Range:     0 to 40 mV (PAR); 0 to 20 mV (Far-Red)

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 1 ms

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