The SQ-224 is an amplified sensor with a 4-20 mA output and exhibits excellent cosine response. The sensor was designed for use in environments with significant background electrical noise that can be found in many industrial applications.
|Power Supply||5-36V DC with a maximum current drain of 22mA (2mA quiescent current drain)|
|Sensitivity||0.0064 mA per µmol m-2s-1|
|Calibration Factor||156 µmol m-2s-1 per mA (reciprocal of sensitivity)|
|Measurement Repeatability||< 1%|
|Non-Stability (Long-term Drift)||< 2% per year|
|Response Time||< 1 ms|
|Field of View||180°|
|Spectral Range||410nm to 655nm (wavelengths where response is greater than 50% of maximum|
|Directional (Cosine) Response||±5% at 75° zenith angle|
|Temperature Response||0.06 ± 0.06% per °C|
|Operating Environment||-40 to 70°C, 0 to 100% Relative Humidity, Can be submerged in water up to depths of 30m|
|Dimensions||2.4cm diameter and 2.8cm height|
|Mass||140g (with 5m of lead wire)|
|Cable||5m of shielded, twisted-pair wire. Santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions), Pigtail lead wires|
The sensor measures photosynthetically active radiation and is calibrated for use under electric lights. The sensor housing design features a fully potted, domed-shaped head making the sensor fully weatherproof and self-cleaning. Photosynthetically active radiation (PAR), or photosynthetic photon flux (PPF), is the wavelength range from 400 to 700 nanometers and is strongly correlated with plant growth. Gardeners, greenhouse managers, growth chamber users and salt-water aquarists measure PAR to insure optimal specimen health.
Mean cosine response of twenty-three SQ series quantum sensors (error bars represent two standard deviations above and below mean).
Cosine response measurements were made by direct side-by-side comparison to the mean of four reference thermopile pyranometers, with solar zenith angle-dependent factors applied to convert total shortwave radiation to PPFD. Blue points represent the AM response and red points represent the PM response.
Mean spectral response of six SQ series quantum sensors (error bars represent two standard deviations above and below mean) compared to PPFD weighting function. Spectral response measurements were made at 10nm increments across a wavelength of 300 to 800nm in a monochromator with an attached electric light source. Measured spectral data from each quantum sensor were normalised by the measured spectral response of the monochromator/electric light combination, which was measured with a spectroradiometer.
Mean temperature response of eight SQ series quantum sensors (error bars represent two standard deviations above and below mean). Temperature response measurements were made at 10°C intervals across a temperature range of approximately -10 to 40°C in a temperature controlled chamber under a fixed, broad spectrum, electric lamp. At each temperature set point, a spectroradiometer was used to measure light intensity from the lamp and all quantum sensors were compared to the spectroradiometer. The spectroradiometer was mounted external to the temperature control chamber and remained at room temperature during the experiment.