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.
ISO 9060:2018: Class C (previously known as second class)
Input Voltage Requirement: 5.5 to 24 V DC
Current Drain: 1.3 mA (quiescent), 1.8 mA (active)
Output Range: 0 to 2000 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 2000 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: 30.5 mm diameter, 37 mm height
Mass (with 5 m of cable): 140 g
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
Warranty: 4 years against defects in materials and workmanship
