SP-722-SS Modbus Digital Output Thermopile Albedometer

Apogee's new Modbus albedometer is a cost-effective solution for horizontal and plane of array performance monitoring of bifacial solar panels. Consisting of an Apogee Instruments SP-510 and SP-610 thermopile pyranometer, the SP-722-SS can be easily mounted to a mast or directly to a solar panel with one of the available mounting brackets.

The SP-722-SS is a thermopile albedometer with a digital signal using Modbus RTU protocol over RS-232 or RS-485. For mounting directly to a solar panel, we recommend using the AM-150 albedometer solar panel clamping bracket. To mount to a mast, use the AM-500 Net Radiometer mounting bracket or the AM-240 Rod based mounting fixture.

Albedo measurements indicate the broadband shortwave reflectivity of materials and are used to monitor bifacial solar panels, understand heat retention in urban and architectural settings, and study climate and weather. Typical applications for pyranometers include shortwave radiation measurement in agricultural, ecological, and hydrological weather networks.

The SP-722-SS includes an IP68 marine-grade stainless-steel cable connector to simplify sensor removal and replacement for maintenance and recalibration.

ISO 9060:2018: Class C (fast response; upward-looking), N/A (downward-looking)
Power Supply: 5.5 to 24 V DC
Current Draw: RS-232 quiescent 37 mA, active 37 mA; RS-485 quiescent 37 mA, active 42 mA
Calibration Uncertainty at 1000 W mˉ²: Less than 3 %
Output Range: Modbus
Measurement Range: 0 to 2000 W mˉ²
Measurement Repeatability: Less than 1 %
Long-term Drift: Less than 2 % per year
Non-linearity: Less than 1 %
Field of View: 180˚ (upward-looking), 150˚(downward-looking)
Spectral Ranges: 385 nm to 2105 nm (upward-looking), 370 nm to 2240 nm (downward-looking)
Directional (Cosine) Response: Less than 30 W mˉ² at 80˚ solar zenith (upward-looking), Less than 20 W mˉ² for angles between 0 to 60˚ (downward-looking)
Temperature Response: Less than 5 % from -15 to 45 C
Zero Offset A: Less than 2 W mˉ², Less than 10 W mˉ² (heated)
Zero Offset B: Less than 5 W mˉ²
Uncertainty with Daily Total: Less than 5 %
Operating Environment: -50 to 80 C; 0 to 100 % relative humidity
Heater: 390 Ω, 30.8 mA current draw and 370 mW power requirement at 12 V DC
Dimensions: 66.5 mm height, 74.4 mm length, 33 mm width
Mass (with 5 m of cable): 247 g
Cable: 5 m of four 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 Manufactured: Assembled in the USA