The SPN1 Pyranometer is a patented, meteorological class instrument, with built-in heater, designed for long-term outdoor exposure. It is an affordable alternative to shade-ring pyranometers, pyrheliometers and traditional sunshine recorders. The SPN1 is exceptionally easy to use; it needs no routine adjustment or polar alignment and works at any latitude.
Unique design
The Sunshine Pyranometer uses an array of seven, miniature thermopile sensors and a computer-generated shading pattern to measure the direct and diffuse components of incident solar radiation. The shading pattern and thermopiles are arranged so that at least one thermopile is always fully exposed to the solar beam, and at least one is fully shaded from it, regardless of the position of the sun in the sky. All seven thermopiles receive an equal amount of diffuse light. From the individual thermopile readings, a microprocessor calculates the global and diffuse horizontal irradiance and from these values an estimate of sunshine state is made.
Outputs
The Sunshine Pyranometer provides 2 analogue voltage outputs for global and diffuse radiation, and a digital output for sunshine duration, which can be connected to data loggers, such as the Delta-T GP2 and GP1. Readings can also be obtained directly from the RS232 port.
Heater
An internal heater keeps the dome clear of dew, ice and snow down to -20°C (in still air conditions), ensuring reliable readings in difficult climatic conditions.
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Overall accuracy: Global (Total) and Diffuse radiation
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±5% Integrals daily
±5% ±10 W.m-2 Hourly averages
±8% ±10 W.m-2 Individual readings
Accuracy figures give 95% confidence limits, i.e., 95% of individual readings will be within stated limits under normal climatic conditions.
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Resolution
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0.6 W.m-2 = 0.6mV
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Range
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0 to >2000 W.m-2
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Analogue output sensitivity
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1mV = 1 W.m-2
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Analogue output range
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0-2500mV
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Sunshine status threshold
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120 W.m-2 in the direct beam
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Accuracy: Sunshine status
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±10% sun hours with respect to the threshold
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Accuracy: Cosine Correction
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±2% of incoming radiation over 0-90° Zenith angle
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Accuracy: Azimuth angle
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± 5% over 360° rotation
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Temp coefficient
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± 0.02% per °C typical (-20 to +70°C)
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Temperature range 1
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-40 to +70°C
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Recalibration / stability
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Factory recalibration recommended every 2 years.
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Response time
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< 200ms>
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Spectral response
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400-2700nm
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Spectral sensitivity variation
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10% typical
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Non-linearity
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<1>
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Tilt response
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Negligible errors
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Zero offsets
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<3>-2 for a change of 5°C/hr in ambient temperature
<3>-2 dark reading
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Latitude capability
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-90° to +90°
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Environmental
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IP67 sealing
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Sunshine status output
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No sun = open circuit
Sun = short circuit to ground
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Power requirement
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2mA (excluding heater power), 5V – 15V DC
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Heater power
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12V – 15V DC, up to 1.5A
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Heater control
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Continuously variable up to 20W
output for external temperatures below 0°C
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Lowest snow & ice- free temperatures
(with heater in use)
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-20°C at 0 m/s wind speed
-10°C at 2 m/s wind speed
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Mounting options:
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3 x M5 tapped holes in base: 108mm pcd, 120°spacing
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Size & weight
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140mm dia x 100mm (h), 940g
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