The BF5 Sunshine Sensor measures Global and Diffuse radiation and sunshine duration.
Unique design
The Sunshine Sensor is a patented design*. It uses an array of photodiodes with a unique computer generated shading pattern to measure incident solar radiation. A microprocessor calculates the Global and Diffuse components of the radiation and determines the sunshine status. A built-in heater keeps the BF5 clear of dew, ice and snow down to 20°C.
Outputs
Two analogue voltage outputs are provided for the Global and Diffuse radiation. The sunshine state is represented by a digital output (contact closure). The three outputs can be connected to appropriate channels on data loggers e.g., the Delta T GP2, or other loggers commonly used for environmental monitoring.
Meteorology
The BF5 sensor can be used as an additional sensor with a conventional Met Station. The weather station logger is used to record Global (Total) and Diffuse radiation and the sunshine state (or duration). Power for the sensor comes from its internal alkaline batteries or alternatively from the weather station logger battery. Typically the data will be used for Global and Diffuse radiation, and the sunshine hours during the day (see chart opposite). Direct beam radiation is calculated from Total minus Diffuse. Radiation output units can be preset to energy or PAR or illuminance.
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Accuracy and Resolution of analogue radiation outputs
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PAR
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Energy
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Illuminance
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Units
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mmol.m-2.s-1
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W.m-2
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klux
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Overall accuracy: Total
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±10 mmol.m-2.s-1 ±12%
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±5 W.m-2 ±12%
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±0.600 klux ±12%
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Overall accuracy: Diffuse
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±10 mmol.m-2.s-1 ±15%
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±20 W.m-2 ±15%
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±0.600 klux ±15%
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Resolution
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0.6 mmol.m-2.s-1
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0.3 W.m-2
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0.060 klux
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Range
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0 - 2500 mmol.m-2.s-1
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0 - 1250 W.m-2
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0 - 200 klux
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Output sensitivity
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1mV = 1 mmol.m-2.s-1
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1mV = 0.5 W.m-2
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1mV = 0.100 klux
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Output range
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0 – 2500 mV
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0 – 2500 mV
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0 – 2000 mV
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Accuracy: Sunshine hours
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±10% (WMO definition)
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Accuracy: Cosine correction
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±10% 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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Temperature coefficient
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± 0.15 % /°C typical
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Temperature range
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-20 to + 50°C, Alkaline batteries
-20 to + 70°C, Lithium batteries
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Recommended recalibration interval
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2 years
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Response time
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< 250ms>
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Spectral response
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400 - 700nm
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Latitude capability
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-90° to + 90°
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Environmental : Sealing
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IP65 ( shower and dust proof)
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Sunshine status : contact closure
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No sun = open circuit
Sun = short circuit to ground
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Internal battery
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2 x 1.5V AA Alkaline batteries
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Power requirement
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2mA, (awake ), <30>uA (asleep)
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Battery lifetime
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1 year typical
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Input voltage range
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1.4 - 3.6V DC, internal battery
5.0 - 15V DC, external power
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Fuse trip point, on sunshine status signal
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0.5A, 30V self resetting (switch- closure mode)
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Max applied voltage to sunshine status output
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0 to 24V (contact closure mode)
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RS232 connector
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5 pin M12
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Signal output & power-in connector
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8 pin M12
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Mounting options:
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Camera tripod socket, ¼” Whitworth Holes for 4 x M4 bolts at box corners
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Size & Weight
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120mm x 122mm x 95mm, 635g
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Heater output below 0°C
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15 W
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Heater output above 5°C
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2W reducing to 0W at 35°C
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Lowest snow & ice-free temperatures
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-20°C at 0 m/s wind speed
-10°C at 2 m/s wind speed
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Heater: max power
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15 W at 12V DC
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Heater: max current
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1.5A at 15V
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Fuse: max voltage, current
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24V, 1.6A (self resetting)
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Heater Input voltage
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12 to 15V DC
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