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BF5 User Manual v 2.3 

Appendix A: Design and Test Summary 

 43 

Total from the PAR Total, at the stated accuracy of the instrument. 
However, the spectral distribution of Diffuse light does vary considerable 
between blue sky and overcast conditions. To take this into account, the 
BF5 uses the Beam Fraction (Direct / Total) as an estimator of the 
proportion of blue skylight, and applies a conversion dependent on this 
value. The actual conversion factors used are: 
Energy TOTAL = PAR TOTAL * 0.48 

 

Energy DIFFUSE = PAR DIFFUSE * (0.48 – 0.48 * (Beam Fraction)

4

 ) 

These values have been derived from long term measurements against 
Kipp energy sensors fitted with shade rings, at a number of different sites, 
over a wide range of conditions. 

Illuminance units (lux) 

The human eye response curve covers the same spectrum range as PAR. 
A single conversion factor to lux is used (1 

mol.m

-2

.s

-1

 

= 55.7 lux). This 

has been derived theoretically from a range of different daylight spectra 
measured with a LiCor spectroradiometer in a range of conditions. The 
varying spectral distribution of, for example, blue skylight, overcast 
skylight, or Direct beam sunlight at sunset, only cause a 1% - 2% variation 
from this, which is well within the specified instrument accuracy. 

Sunshine state 

The WMO definition of sunshine presence is that there is greater than 120 
W.m

-2

 

in the Direct beam, measured perpendicular to the beam. This 

cannot be measured directly by a horizontal cosine corrected sensor. The 
BF5 uses the following algorithm, which has been found to give good 
results when compared with the WMO definition, and substantially more 
accurate than measurements using a Campbell-Stokes recorder. 
Sunshine presence if  

 

Total/Diffuse > 1.25  
and    
Total > 50 

mol.m

-2

.s

-1

  

 

 

Содержание BF5

Страница 1: ...User Manual for the Sunshine Sensor type BF5 Delta T Devices Ltd BF5 UM 2 3 ...

Страница 2: ...Conformity The BF5 Sunshine Sensor conforms to EU regulations regarding electromagnetic emissions and susceptibility and is CE marked by Delta T Devices Ltd For certificates look on our website at www delta t co uk or the Delta T Software and Manual DVD Warnings To maintain conformance to CE standards the equipment must be used as described in this manual Modifications to the equipment may invalid...

Страница 3: ...s 11 Mounting 11 Cables 11 Power Considerations 12 Heater 13 Getting Started 15 PC software 15 SunRead Installation 15 Connect your BF5 16 Preliminary Checks 17 Battery and Desiccant 17 Check the Dome 17 Use with SunScan 18 Setting up the BF5 18 Connecting to SunScan 18 Environment and Moisture protection 19 Use with a data logger 20 Effect of engineering units on sensitivity and resolution 20 Sun...

Страница 4: ... Sunscan cable and BF5 Logger Cables 31 RS232 Serial Cable 31 Serial Extension Cable 32 Telescopic Tripod 32 Cross Arm for Mast Mount 32 Cosine response 33 Spectral response 34 Routine Maintenance 35 Batteries 35 Desiccant 35 Maintaining the dome 35 Recalibration of BF5 35 Warranty and Service 38 Terms and Conditions of Sale 38 Service and Spares 39 Technical Support 39 Contact details 39 Problems...

Страница 5: ...BF5 User Manual v 2 3 Contents 5 Molar units mol m 2 s 1 42 Energy units W m 2 42 Illuminance units lux 43 Sunshine state 43 Glossary 48 Index 49 ...

Страница 6: ...e also on the Software and Manuals DVD Description and Functions What it measures The BF5 Sunshine Sensor is one sensor with three output channels 1 Total global solar radiation 2 Diffuse radiation 3 Sunshine status The Direct beam component of solar radiation can be calculated from the Total minus the Diffuse component You can set up the two radiation outputs to give millivolt signals scaled to t...

Страница 7: ...ngs It does not need to be oriented towards North It will work accurately in any orientation as long as it is mounted horizontally It does not require knowledge of the Latitude or Longitude and can be used at any Latitude or Longitude It measures sunshine hours as well as Total and Diffuse radiation A heater allows use in condensing and frosty situations SunRead software SunRead runs on a PC runni...

Страница 8: ...PAR photodiodes and an adjustable shadow band It measured Total and Diffuse PAR It required alignment to true North and the shadow band required frequent adjustment The BF2 design measured Total and Diffuse PAR without needing any adjustment or North alignment only horizontal levelling The BF2 also measured Sunshine state The BF3 used the same optical design as the BF2 but gave the user a choice o...

Страница 9: ...frost and condensation Its use is recommended for logging applications It requires a separate external 12V DC power supply Use of the heater stabilises the internal temperature of the BF5 in cold conditions keeping the dome free of frost and resulting in greater measurement accuracy The heater consists of two 15W resistors fixed to the shadow mask When power is applied to the heater it works as fo...

Страница 10: ...10 Introduction BF5 User Manual v 2 3 Cable connectors and components inside the dome Section through BF5 showing internal PCBs and battery pack ...

Страница 11: ...Cables Separate cables and extension cables are available for connecting the BF5 to a PC to SunScan and to a data logger as shown in the diagram above The logger cable can also be used to connect external power to the BF5 sensor e g logger warmup power and separately to connect power to the BF5 heater For full details see BF5 SunScan Cable on page 31 See also the BF5 Quick Start Guide RS232 cable ...

Страница 12: ...hese are optional 2 Power from the data logger This only needs to be applied when the logger takes a reading The BF5 s Total Diffuse and Sun analogue outputs are valid 100ms after power is applied and are then updated every 250ms These analogue outputs are only enabled when there is a voltage present on the data logger power input via DL Power 3 Power from a 12V heater supply ...

Страница 13: ...s available from elsewhere e g from the heater supply See also the BF5 Quick Start Guide Heater The BF5 is fitted with an internal thermostatically controlled heater for protection against frost and condensation The heater is mounted on the shadow mask which will transfer heat around the inside of the dome and the top of the enclosure When power is applied to the heater supply cables it works as f...

Страница 14: ...can consume 1 5A at 12V DC so a 40 Ah car battery will only last about one day For extended data logging in cold climates we recommended that you power the heater via a 12V DC output supply which is itself powered from the mains Warning Do not apply AC mains power to the BF5 Warning Ensure the heater ground is isolated from all other BF5 ground connections If possible use a data logger with differ...

Страница 15: ...s in the base of the BF5 plastic housing or Use the BF5 M cross arm This is compatible with the Delta T 2m weather station mast and with many builder s scaffolding systems See also the BF5 Quick Start Guide PC software The SunRead software runs under Microsoft Windows 98 or later with a free RS232 port or USB Serial adapter SunRead Installation You need SunRead version 1 5 or later This is provide...

Страница 16: ... will be displayed and power supply voltage and readings will be updated every few seconds Status information eg not connected or BF5 serial number Selects from the available serial ports Sets up data logging either to PC or built in logger if fitted Software version numbers Firmware version reported by BF5 Battery voltage if batteries are fitted otherwise external power supply voltage Total Diffu...

Страница 17: ...and should be replaced If the voltage is in between use your judgement The battery voltage can also be measured with a voltmeter after undoing the four retaining screws in the lid If the BF5 temperature is likely to exceed 50 C you are advised to replace the Alkaline batteries with 1 5V Lithium batteries This is because the capacity of Alkaline batteries is poor above 50 C WARNING Do not use 3 6V ...

Страница 18: ...Levelling The BF5 is equipped with a miniature bubble level The tripod supplied type BFT1 has 3 axis adjustment to facilitate levelling The sensor is level when the bubble is within the central circle It is more important to level the BF5 accurately than the SunScan probe Connecting to SunScan Options Use cable type EXT 8w 05 with optional extension cables type EXT 8w xx where x 5 10 or 25m to con...

Страница 19: ...batteries when using the BF5 with SunScan as SunScan does not provide enough external power to operate the BF5 reliably Environment and Moisture protection Avoid putting the BF5 or any SunScan system components at risk when working outdoors Minimise as far as practical their exposure to high or rapidly changing temperatures The BF5 is designed to resist dust and water jets IP65 but is not hermetic...

Страница 20: ...being applied via the Power wire Where daytime temperatures fall below zero or inaccuracies due to condensation are undesirable make provision to provide power to the heater via cable type SP BF w05 The heater power supply must be isolated not sharing any earth return with the BF5 sensor outputs Effect of engineering units on sensitivity and resolution The choice of output units has an effect on o...

Страница 21: ...utputs are active 100ms after a voltage is applied to the data logger power cable and then updated every 250ms The Total and Diffuse outputs have a range of 0V 2 5V with an internal resistance of 100 There is also some protection on these outputs if they are taken outside their normal range These outputs should be measured by a high impedance voltage input channel with SigGND taken to the negative...

Страница 22: ... use then the Signal Gnd must be able to float relative to the two power grounds at the logger end Use a data logger with differential sensor inputs to avoid potential errors caused by an incorrectly wired heater earth return Alternately if you have to use a single ended logger the requirement is that either the logger or the heater PSU must be able to float relative to the other and there must be...

Страница 23: ...or ground by an inductor to protect it from any noise in the heater circuit The serial port lines have basic ESD protection Suggested power supply connections For use with a data logger the DL Power line has to be at 5V or more to enable the analogue outputs The power required can be taken either from the DL Power line or the heater supply For most logging situations one of the following two conne...

Страница 24: ...y point is that the various grounds Htr DL Gnd Signal Gnd are connected at the BF5 so if the heater is in use then the Signal Gnd must be able to float relative to the two power grounds at the logger end This is achieved easily with a differential input For a single ended logger the requirement is that either the logger or the heater PSU must be able to float relative to the other and there must b...

Страница 25: ... to logger ground so you should take care only to connect this to SigGND if the logger is not supplying power for the BF5 Otherwise power supply currents may flow through the SigGND cable which may cause voltage offsets on the Total and Diffuse readings with long cable lengths 2 Logger resistance input If the logger has no digital inputs but can measure resistance then the Sun output can be measur...

Страница 26: ...nnel Sun present 0 V no sun 5 V Note Your logger must be able to read the voltage going into the resistor If it is too high use a potential divider 4 Switching an external load If for any reason you want to use the Sun output to switch a high current load you should make sure that the current return path is through the DL Gnd wire and not the SigGND wire otherwise you may see large offset voltages...

Страница 27: ... connection Earthing and screen connections The braided screen of the 8 core analogue cable type SP BF w 05 is connected to the BF5 electronics internally The screen is connected to the sensor ground by an 18V transient suppressor to minimise the possibility of high voltages relative to the internal circuitry if there are nearby lightning strikes In general the screen black wire should be connecte...

Страница 28: ...e online GP2 Tutorial videos at www delta t co uk DL2e logger See BF5 DL2e wiring connections in the online sensor library of the Ls2Win PC software SR7 service release 7 on the Delta T Software and Manuals CD Note If upgrading from an earlier service release of Ls2Win you will need to reinstall the sensor library This is described in the online Ls2Win Release Notes installed with Ls2Win and which...

Страница 29: ... climatic conditions Output setting PAR Energy Illuminance Units mol m 2 s 1 W m 2 klux Overall accuracy Total 10 mol m 2 s 1 12 5W m 2 12 0 600 klux 12 Overall accuracy Diffuse 10 mol m 2 s 1 15 20W m 2 15 0 600 klux 15 Resolution 0 6 mol m 2 s 1 0 3 W m 2 0 060 klux Range 0 2500 mol m 2 s 1 0 1250 W m 2 0 200 klux Analogue output sensitivity 1mV 1 mol m 2 s 1 1mV 0 5 W m 2 1mV 0 100 klux Analogu...

Страница 30: ...eries Power requirement 2mA awake 30 A asleep Battery Lifetime 1 year typical Input Voltage Range powered from internal battery 1 4 to 3 6V DC Input Voltage Range external power 5 to 15V DC Fuse trip point on sunshine status signal when in switch closure mode 0 5A 30V self resetting Max applied voltage to sunshine status output in contact closure mode 0 to 24V RS232 connector 5 pin M12 Signal outp...

Страница 31: ...tension Cables Can be used to extend both BF5 Sunscan cable and BF5 Logger Cables Type EXT 8w 05 Length 5 m Termination 8 pin M12 female combined power and signal cable to 8 way M12 male for logger terminals and or heater power supply Type EXT 8w 10 Length 10 m Termination 8 pin M12 female combined power and signal cable to 8 way M12 male for logger terminals and or heater power supply Type EXT 8w...

Страница 32: ... male Telescopic Tripod Type BFT1 Max height 1 73 m Closed length 0 68 m Weight 2 5 kg Screw mount inch Whitworth socket Cross Arm for Mast Mount Type BF5 M Length diameter material 1m long 1 inch dia grey anodised aluminium Cross arm connector 1 x 2 inch KeeKlamp type 45 86 Saddle washers 2 Bolt 1 inch long x inch BSW stainless steel hex head Adjustable Camera Mount 1 4 inch BSW camera thread wit...

Страница 33: ... 2 3 Technical reference 33 Cosine response 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 1 1 1 2 0 10 20 30 40 50 60 70 80 90 Zenith angle in degrees Ideal cosine reponse BF5 actual response BF5 Actual Ideal Cosine Response ...

Страница 34: ...34 Technical reference BF5 User Manual v 2 3 Spectral response ...

Страница 35: ...ging frequency Do not leave the BF5 with exhausted batteries in it they may leak Desiccant The dryness of the desiccant pack is indicated by a coloured panel under the dome Blue indicates dry pink indicates that renewal is needed To regenerate the desiccant The desiccant pack can be regenerated by heating Remove the pack from the BF5 and heat in an oven for a few hours at about 90ºC Allow it to co...

Страница 36: ...36 Technical reference BF5 User Manual v 2 3 ...

Страница 37: ...ard sensor but this is difficult and not recommended You will need stable sunlight or a stable sunlight simulator Natural atmospheric turbulence can cause rapid variations in sunlight intensity which if greater than the quoted accuracy of the BF5 could make it impossible to recalibrate in sunshine ...

Страница 38: ...harge or by repairing the goods free of charge at Delta T s premises in the UK during the warranty period If Delta T requires that goods under warranty be returned to them from overseas for repair Delta T shall not be liable for the cost of carriage or for customs clearance in respect of such goods However we much prefer to have such returns discussed with us in advance and we may at our discretio...

Страница 39: ...forwarded to our original supplier for specialist repairs or recalibration additional delays of a few weeks may be expected Technical Support Technical Support is available on Delta T products and systems Users in countries that have a Delta T Distributor or Technical Representative should contact them in the first instance Technical Support questions received by Delta T will be handled by our Tec...

Страница 40: ...nderside of the case The internal software version number is displayed in the About box using SunRead Troubleshooting BF5 Not Responding Check cables and connectors If using a PC check that you are using the SP BF RS01 serial cable 5 pin M12 to DB9 and that it is plugged into the same serial port on your PC that you have selected in the SunRead software If using an external logger check the logger...

Страница 41: ...cross the sky for that day or using an occluding disk held on a robot arm Both of these approaches require accurate alignment to the Earth s axis and regular adjustment Another well established approach is the Campbell Stokes recorder which uses a glass sphere to focus the Direct solar beam onto a recording chart causing a burn which indicates direct beam strength Design objectives The aim of the ...

Страница 42: ...ffuse radiation the minimum reading represents half of the Diffuse radiation The outputs are calculated as follows Total Direct Diffuse MAX MIN Diffuse 2 MIN 1 05 the 1 05 factor compensates for calibration variations between photodiodes and also variability in the intensity distribution of the diffuse sky If Diffuse Total then Diffuse Total to make sure Diffuse is never more than Total Direct Tot...

Страница 43: ...se curve covers the same spectrum range as PAR A single conversion factor to lux is used 1 mol m 2 s 1 55 7 lux This has been derived theoretically from a range of different daylight spectra measured with a LiCor spectroradiometer in a range of conditions The varying spectral distribution of for example blue skylight overcast skylight or Direct beam sunlight at sunset only cause a 1 2 variation fr...

Страница 44: ...nster Derbyshire 20 31 May 1999 The graph plots hourly averages of readings every 5 seconds Note the offset Y axis to separate the Total and Diffuse plots Hourly Averages y 0 980x R 2 0 994 y 0 990x R 2 0 994 200 0 200 400 600 800 1000 1200 1400 0 200 400 600 800 1000 1200 1400 1600 QS umol m 2 s 1 BF2 Diffuse umol m 2 s 1 0 200 400 600 800 1000 1200 1400 1600 BF2 Total umo m 2 s 1 ...

Страница 45: ...sity Edinburgh between February and July 2001 The graph plots hourly averages of readings every 10 seconds Note the offset Y axis to separate the Total and Diffuse plots Hourly averages y 1 014x R 2 0 980 y 1 047x R 2 0 994 300 200 100 0 100 200 300 400 500 600 0 100 200 300 400 500 600 700 800 900 Kipp Global Diffuse W m 2 BF3 Diffuse W m 2 0 100 200 300 400 500 600 700 800 900 BF3 Global W m 2 ...

Страница 46: ...shows a comparison of a BF3 Total output against a LiCor Illuminance sensor Data recorded at Burwell Cambridge UK 16 23 Aug 2001 The graph plots 5 minute averages of readings every 5 seconds 5 minute averages y 1 029x R 2 0 997 0 20 40 60 80 100 120 0 20 40 60 80 100 120 LiCor klux BF3 klux ...

Страница 47: ...3 compared to the WMO definition of 120 W m 2 in the Direct beam Data recorded at Napier University Edinburgh between February and July 2001 Comparable data from an adjacent Campbell Stokes recorder is also plotted Daily sunshine totals 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 WMO Sunshine Hrs Sunshine Hrs BF3 Campbell Stokes ...

Страница 48: ...of wavelength It is measured in units of W m 2 The normal daylight maximum is a little over 1000 W m 2 Illuminance radiation in the visible range 400nm 700nm measured with the same spectral sensitivity as the human eye It is measured in units of lux or klux 1000 lux The normal daylight maximum is about 150 klux PAR Photosynthetically Active Radiation is visible light of wavelength 400nm 700nm with...

Страница 49: ...ntrol use of sunshine output to switch an external load 26 Copyright 2 Cosine response 33 49 D Data logger Use with 20 Desiccant 17 35 Diffuse light 49 Direct beam 49 DL2e Logger 28 DL6 Logger 28 E Earthing 27 Energy 6 7 8 20 49 Energy units 43 Environment and Moisture protection 19 F Full scale 20 G GP1 Logger 28 Ground connection options 27 H Heater 9 13 specifications 30 I Illuminance 6 7 8 20 ...

Страница 50: ...ice and Spares 40 software 15 Specifications 29 Spectral response 34 Spectral Response 30 SPN1 w 05 pin outs and wiring 21 sun output 21 wiring connection options 25 SunData 49 SunRead 7 SunScan 18 49 SunScan probe 18 Sunshine 49 Sunshine state 44 Sunshine status 30 Sunshine Status 20 T Technical Support 40 Temperature coefficient 30 Temperature range 30 Total radiation 49 Tripod 18 32 Troubleshoo...

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