The SP-421 is a digital sensor with SDI-12 communication protocol. The sensor incorporates a silicon-cell photodiode with a rugged, self-cleaning sensor housing design. Typical applications include shortwave radiation measurement in agricultural, ecological, and hydrological weather networks. Sensors are also used to optimize photovoltaic systems. Sensor includes IP68 marine-grade stainless-steel cable connector 30 cm from head to simplify sensor removal and replacement for maintenance and recalibration.
Google's Project Loon
Apogee's SP-230 heated pyranometer was selected to monitor PV panels on Project Loon.
Monitoring PV Panels on Jin Jeop Library
SP-110's are integrated as part of a PV monitoring sytem for a PV power generation facility on the roof of the Jin Jeop library in Korea.
Solar Power Plants on Lakes and Dams
Studying solar radiation at different angles to determine locations for solar power plants.
Pyranometer mounted on model train to collect measurements in orchard for irrigation study.
ISO 9060:2018 Class C (previously known as second class) Input Voltage Requirement 5.5 to 24 V DC Current Drain 0.6 mA (quiescent), 1.3 mA (active) Output Range 0 to 1750 W mˉ² Calibration Uncertainty ± 5 % Measurement Repeatability Less than 1 % Non-stability (Long-term Drift) Less than 2 % per year Non-linearity Less than 1 % (up to 1750 W mˉ²) Response Time 0.6 s, time for detector signal to reach 95 % following a step change, fastest data transmission rate for SDI-12 circuitry is 1 s 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 44 mm height, 23.5 mm diameter Mass 177 g (with 5 m cable) Cable 5 m of two conductor, shielded, twisted-pair wire, additional cable available in multiples of 5 m; TPR jacket (high water resistance, high UV stability, flexibility in cold conditions); pigtail lead wires