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Enabling better global research outcomes in soil, plant & environmental monitoring.

SP-420 Smart Pyranometer

The new SP-420 smart pyranometer can be connected directly to a computer for taking spot measurements or graphing and datalogging real-time shortwave radiation using the included software. The sensor can also act as a stand-alone shortwave radiation datalogger by simply connecting it to any standard 5 V DC USB power plug. Internal memory within the sensor head is capable of storing 10,000 user-specified periodic measurements that can be downloaded as a CSV file to a computer for analysis.

Applications include shortwave radiation measurement in agricultural, ecological, and hydrological weather networks. Sensors are also used to optimise photovoltaic systems.

Internal Data Storage
The sensor has internal data storage capability with the ability to hold up to 10,000 measurements. This allows the sensor to collect data while connected to a stand-alone 5 V DC power supply such as a USB wall adapter.

No Datalogger Required
The sensor can be connected to a desktop or laptop computer via USB 2.0 type A plug to be used with the ApogeeConnect software. The included Apogee software gives the user control of data logging and calibration settings, provides a real time output display and graph of shortwave radiation measurements and allows the data set to be saved as a csv file.

Accurate, Stable Measurement
Calibration in controlled laboratory conditions is traceable to the World Radiometric Reference in Davos, Switzerland. Pyranometers are cosine-corrected with directional errors less than ± 5 % at a solar zenith angle of 75°. Long-term non-stability determined from multiple replicate pyranometes in accelerated aging tests and field conditions is less than 2 % per year.

Rugged, Self-cleaning Housing
Patented domed shaped sensor head (diffuser and body) facilitate runoff of dew and rain to keep the diffuser clean and minimise errors caused by dust blocking the radiation path. Sensors are housed in a rugged anodised aluminium body and electronics are fully potted.

Resolution: 0.1 W m-2
Calibration Factor: Custom for each sensor and stored in firmware
Calibration Uncertainty: ± 5 %
Measurement Repeatability: Less than 1 %
Long-term Drift (Non-stability): Less than 2 % per year
Non-linearity: Less than 1 % (up to 1750 W m-2)
Response Time: Software updates every second
Field of View: 180°
Spectral Range: 360 to 1120 nm (wavelengths where response is 10 % of maximum)
Directional (Cosine) Response ± 5 % at 75° zenith angle
Temperature Response: 0.04 ± 0.4 % per °C
Operating Environment: -40 to 70°C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m
Dimensions: 24 mm diameter, 27.5 mm height
Mass: Sensor head weighs 90 g
USB Cable: 4.6 m (15 ft)
Current Draw (when Logging): 2.1 mA
Warranty: 4 years against defects in materials and workmanship

Calibration Traceability

Apogee Instruments SP series pyranometers are calibrated through side-by-side comparison to the mean of four Apogee SP-110 transfer standard pyranometers (shortwave radiation reference) under high intensity discharge metal halide lamps. The transfer standard pyranometers are calibrated through side-by-side comparison to the mean of at least two ISO-classified reference pyranometers under sunlight (clear sky conditions) in Logan, Utah. Each of four ISO-classified reference pyanometers are recalibrated on an alternating year schedule (two instruments each year) at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. NREL reference standards are calibrated to the World Radiometric Reference (WRR) in Davos, Switzerland.