Solar radiation at Earth's surface is typically defined as total radiation across a wavelength rage of 280 to 4000 nm (shortwave radiation). Total solar radiation, direct beam and diffuse, incident on a horizontal surface is defined as global shortwave radiation, or shortwave irradiance (incident radiant flux), and is expressed in Watts per square meter (W m-2, equal to Joules per second per square meter).
Pyranometers are sensors that measure global shortwave radiation. Apogee series pyranometers are silicon-cell pyranometers, and are only sensitive to a portion of the solar spectrum, approximately 350-1100 nm (approximately 80 % of total shortwave radiation is within this range). However, silicon-cell pyranometers are calibrated to estimate total shortwave radiation across the entire solar spectrum. Silicon-cell pyranometer specifications meet the International Organization of Standardization (ISO) 9060:2018 Class C requirements.
Apogee Instruments SP series pyranometers consist of a cast acrylic diffuser (filter), photodiode, and signal processing circuitry mounted in an anodized aluminum housing, and a cable to connect the sensor to a measurement device. Sensors are potted solid with no internal air space and are designed for continuous total shortwave radiation measurement on a planar surface in outdoor environments. SP series sensors output an analog voltage that is directly proportional to total shortwave radiation from the sun. The voltage signal from the sensor is directly proportional to radiation incident on a planar surface (does not have to be horizontal), where the radiation emanates from all angles of a hemisphere.
SP-110-SS | SP-212-SS | SP-214-SS | SP-215-SS | SP-230-SS | SP-420 | SP-421-SS | SP-422-SS | |
---|---|---|---|---|---|---|---|---|
ISO 9060:2018 | Class C (fast response) | Class C (fast response) | Class C (fast response) | Class C (fast response) | Class C (fast response) | Class C (fast response) | Class C (fast response) | Class C (fast response) |
Power Supply | Self-powered | 5 to 24 V DC | 7 to 24 V DC | 5.5 to 24 V DC | 12 V DC for heater | 5 V | 5.5 to 24 V DC | 5.5 to 24 V DC |
Current Draw | - | 300 µA | 22 mA maximum; 2 mA quiescent | 300 µA | 15.4 mA | 61 mA when logging | 1.5 mA (quiescent); 1.9 mA (active) | RS-232 37 mA; RS-485 quiescent 37 mA, active 42 mA |
Output (Sensitivity) | 0.2 mV per W m-2 | 1.25 mV per W m-2 | 0.008 mA per W m-2 | 2.5 mV per W m-2 | 0.2 mV per W m-2 | - | - | - |
Output Type | 0 to 400 mV | 0 to 2.5 V | 4 to 20 mA | 0 to 5 V | 0 to 400 mV | USB | SDI-12 | Modbus |
Resolution | - | - | - | - | - | 0.1 W m-2 | - | - |
Calibration Factor (Reciprocal of Output) | 5 W m-2 per mV | 0.8 W m-2 per mV | 125 W m-2 per mA, 4 mA offset | 0.4 W m-2 per mV | 5 W m-2 per mV | Custom for each sensor and stored in the firmware | Custom for each sensor and stored in the firmware | Custom for each sensor and stored in the firmware |
Calibration Uncertainty at 1000 W m-2 | Less than 3 % | Less than 3 % | Less than 3 % | Less than 3 % | Less than 3 % | Less than 3 % | Less than 3 % | Less than 3 % |
Measurement Repeatability | Less than 1 % | Less than 1 % | Less than 1 % | Less than 1 % | Less than 1 % | Less than 1 % | Less than 1 % | Less than 1 % |
Long-term Drift | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year |
Non-linearity | Less than 1 % up to 2000 W m-2 | Less than 1 % up to 2000 W m-2 | Less than 1 % up to 2000 W m-2 | Less than 1 % up to 2000 W m-2 | Less than 1 % up to 2000 W m-2 | Less than 1 % up to 2000 W m-2 | Less than 1 % up to 2000 W m-2 | Less than 1 % up to 2000 W m-2 |
Response Time | Less than 1 ms | Less than 1 ms | Less than 1 ms | Less than 1 ms | Less than 1 ms | Software updates every second | Less than 0.6 s | Less than 200 ms |
Field of View | 180° | 180° | 180° | 180° | 180° | 180° | 180° | 180° |
Spectral Range | 360 to 1120 nm | 360 to 1120 nm | 360 to 1120 nm | 360 to 1120 nm | 360 to 1120 nm | 360 to 1120 nm | 360 to 1120 nm | 360 to 1120 nm |
Directional (Cosine) Response | ± 5 % at 75° zenith angle | ± 5 % at 75° zenith angle | ± 5 % at 75° zenith angle | ± 5 % at 75° zenith angle | ± 5 % at 75° zenith angle | ± 5 % at 75° zenith angle | ± 5 % at 75° zenith angle | ± 5 % at 75° zenith angle |
Temperature Response | 0.04 ± 0.04 % per C | 0.04 ± 0.04 % per C | 0.04 ± 0.04 % per C | 0.04 ± 0.04 % per C | 0.04 ± 0.04 % per C | 0.04 ± 0.04 % per C | 0.04 ± 0.04 % per C | 0.04 ± 0.04 % per C |
Operating Environment | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m |
Dimensions | 24 mm diameter, 33 mm height | 30.5 mm diameter, 37 mm height | 30.5 mm diameter, 37 mm height | 30.5 mm diameter, 37 mm height | 24 mm diameter, 33 mm height | 24 mm diameter, 33 mm height | 30.5 mm diameter, 37 mm height | 30.5 mm diameter, 37 mm height |
Mass (with 5 m of cable) | 90 g | 140 g | 140 g | 140 g | 90 g | 90 g | 140 g | 140 g |
How to Choose a Pyranometer
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Lecture 3-Shortwave Radiation and Pyranometers
Introducing Apogee's PV Monitoring Package
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Silicon-cell Pyranometers
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SP-230 All-Season Pyranometer Time Lapse
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Pyranometer User's Guide
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Connecting an SP-214-SS Pyranometer Serial Numbers 9898 and Above to an SMA Cluster Controller
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Solar radiation at Earth's surface is typically defined as total radiation across a wavelength range of 280 to 4000 nm (shortwave radiation). Total solar radiation, direct beam and diffuse, incident on a horizontal surface is defined as global shortwave radiation, or shortwave irradiance (incident radiant flux), and is expressed in Watts per square meter (W m-2).
Pyranometers are sensors that measure global shortwave radiation. Apogee Instruments offers both silicon-cell and black-body thermopile pyranometers. Silicon-cell pyranometers are only sensitive to a portion of the solar spectrum, approximately 360 to 1100 nm (approximately 80 % of total shortwave radiation is within this range).
Typical applications of silicon-cell pyranometers include:
• Agricultural weather networks
• Ecological weather networks
• Hydrological weather networks
Solar, Net, and Photosynthetic Radiation - ASA Agroclimatology
Low Light Calibration Error Notice
How to connect an Apogee SP-214 Pyranometer to an SMA Cluster Controller
Reference Pyranometer Traceability
Apogee Meter Tips and Troubleshooting
Variable Upper and Lower Crop Water Stress Index Baselines for Corn and Soybean
Implications of Mountain Shading on Calculating Energy for Snowmelt using Unstructed Triangular Mesh
A Novel Integrated Solar Desalination System with a Pulsating Heat Pipe
Quantifying Cooling Effects of Facade Greening: Shading, Transpiration and Insulation
Water Use of Juniperus Virginiana Trees Encroached into Mesi Praireis in Oklahoma, USA
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