Related Manuals for Delta-T SunScan SS1
Summary of Contents for Delta-T SunScan SS1
- Page 1 User Manual for the SunScan Canopy Analysis System type SS1-UM-3.4 Delta-T Devices Ltd...
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Page 2: Notices
Copyright All rights reserved. Under the copyright laws, this manual may not be copied, in whole or in part, without the written consent of Delta-T Devices Ltd. Under the law, copying includes translation into another language. Copyright © 2024 Delta-T Devices Limited SunData software and canopy theory are copyright ©... -
Page 3: Table Of Contents
Contents Notices Contents Introduction About this manual Overview Uses Achievable Range Parts and Accessories Summary Description System Connection Options Radio Link connections Testing the Range Trees and Tall Canopies (PAR only) Quick Start Button Actions Alternative ways of controlling SunScan. Change SunData Settings Take LAI Readings Use the Emulator... - Page 4 Direct and Diffuse components Canopy type and BF5 practicalities Canopy type and LAI estimates Canopy sampling volume Preferred light and weather conditions Advice on Absorption and ELADP values SunScan Measurement modes LAI theory Ingredients of the LAI computation method Theory versus reality Derivation of Wood’s SunScan canopy analysis equations The major assumptions Beer's law for canopy absorption...
- Page 5 Telescopic Tripod Carrying Case SunScan Probe Spares Kit type SPS1 BF5 Spares Kit type BF5-SP PAR Performance Appendices A. Logging the probe as a Linear Quantum Sensor B. Logging the Beam Fraction sensor Glossary Technical Support Terms and Conditions of sale Service and Spares Technical Support Contact Details...
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Page 6: Introduction
Introduction About this manual This shows how to use the SunScan Canopy Analyser and its accessories. Also included is the use of the Radio Link option. See also: SunScan Quick Start Guide. BF5 Sunshine sensor User Manual Overview Diffuse Direct Total... -
Page 7: Achievable Range
Fractional Interception You can also measure what fraction of the solar radiation is being intercepted by a plant canopy. For best results include a BF5 Sensor. PAR Mapping You can rapidly find average levels of PAR beneath the canopy, or make linear transects of the PAR distribution within a canopy. -
Page 8: Parts And Accessories
Parts and Accessories Summary SunScan probe no radio SunData software for SDA2 Windows Mobile Ruggedised PDA running Rugged handheld PDA RPDA-1 Windows Mobile 5 or 6 running SunData software. Sunshine Sensor Radio transmitter for BF5-RL4 BF3, links to SS1-RL4 BF5 -links to SS1-RL4 SunScan Probe + radio receiver (434 MHz) links SS1-RL4... -
Page 9: Description
Description SunScan probe The light sensitive “wand” of the probe is 1 metre long, containing 64 photodiodes equally spaced along its length. The probe handle contains batteries and electronics for converting the photodiode outputs into digital PAR readings, which get sent to your PDA via the RS232 link. An optional radio link is available for BF5. - Page 10 Earlier SunData versions run on a PDA, using Windows Mobile 5, 6 and Windows embedded. Please refer to earlier versions of the user manual for instructions on earlier platforms, or contact Delta-T for assistance. Three measurement modes are provided and results can be imported into spreadsheets or other applications for analysis on the PDA or a PC.
- Page 11 Radio Link A 434 MHz radio option links the BF5 to a modified SunScan Probe – useful in situations where a cable is inconvenient. Check with us to see if this radio frequency is approved for use in your country. Note a type SS1-RL4 radio-enabled SunScan is required.
- Page 12 The radio link transmitter module. It also contains batteries. The module case can be dismantled (four corner screws) to access the batteries and to replace a desiccant pack from time to time (see Maintenance section). To switch on, depress the on/off button. The button remains in the depressed position.
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Page 13: System Connection Options
System Connection Options SS1 User Manual v3.4 Introduction 13... -
Page 14: Radio Link Connections
Radio Link connections Transmitter Module and BF5 Fit the BF-RL4 transmitter module on to the mounting plate next to BF5 and mount them both on to the tripod. BF5 LED Serial cable On/off connector Transmitter LED Mounting plate Connect the BF5 transmitter cable to the BF5 serial connector. If you were using the system without radio, disconnect the BF5 to SunScan cable from both the BF5 and the SunScan probe. -
Page 15: Testing The Range
Connect the antenna to the BNC connector on the SunScan handle. Keep the SunScan probe horizontal. The antennas on both the probe and the BF-RL4 module should be approximately vertical. Run the SunData program in the PDA. The receiver will start listening after you take a reading, so the first reading may be bad (showing the incident PAR approximately zero). - Page 16 Check the levelling of the BF5 in these circumstances. This may not be so easy, but do it as well as you can. Restrict your measurements to the time of day when the sun is near zenith. This will minimise levelling errors of the BF5. Tall tree canopies, like forests, present different challenges.
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Page 17: Quick Start
Quick Start Button Actions Alternative ways of controlling SunScan. Figure 1 The PDA with SunScan. SunData actions, such as Read and Store, are activated either by pressing the red SunScan button, or the PDA option. In this picture these “action” buttons are circled in red. Tap on different fields or buttons on screen to change the focus. -
Page 18: Change Sundata Settings
Change SunData Settings Note the Save Settings and Load Settings options in the Settings menu. Use these commands if you intend to pay repeat visits to several different sites, crops or experiments. See also Configuration and data file handling on page 24. Note PAR and ALL Displays may also be used with a BF5 to give fractional interception. -
Page 19: Take Lai Readings
Take LAI Readings SS1 User Manual v3.4 Quick Start 19... - Page 20 Taking readings for estimating Leaf Area Index is simpler with an external beam fraction sensor (BFS) attached, such as the BF5 Sunshine Sensor. Note 1: If no BFS is attached, SunScan initially takes you through an extra step to measure the Beam Fraction. A typical sequence of readings is shown in the diagram below.
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Page 21: Use The Emulator
Use the Emulator For demonstration purposes, the SunData software can be used without the sensors connected. The software can use random values, so users can get used to how the software works without the sensors being used. This is called the Emulator mode This mode simulates having a SunScan attached (with and without an external beam fraction BFS sensor). -
Page 22: Review Data
Review Data Stored data is saved to a file on the PDA. To review your readings, tap the 3 vertical dots at the top right-hand corner of the screen and tap on Review Data and select the viewing app desired (HTML viewer is the easiest). Tap on the scroll bars to see all the data. -
Page 23: Connecting The Pda To Your Pc
Connecting the PDA to your PC Connecting your PDA to a PC lets you transfer your data files and re- install or upgrade the SunData application on your PDA. There are 3 ways you can do this: Using a cable connection (similar to connecting your smart phone to a computer). -
Page 24: Configuration And Data File Handling
The USB stick will now appear as an external drive in Windows explorer, and you can transfer/copy data files from it to the PC (or vice versa). Bluetooth The PDA has Bluetooth functionality so this can be used to transfer files (requires a PC with Bluetooth functionality). -
Page 25: Creating A Configuration File
Use of several configuration files You can save several different configuration files with different names. This is useful if you need to alternate between different sites with different settings. Set up the appropriate titles, settings and a unique data file name for each site or experiment, and save them to separate configuration files. -
Page 26: Data Files
Data Files The first time that SunData runs it will display a message to the effect that it cannot find the data file. This is normal and nothing to worry about, simply click on new datafile to set one up. The default name is Data.txt. A data file is automatically opened whenever you start SunData. -
Page 27: Displaying Data Files On Your Pc
Displaying data files on your PC As soon as you have transferred data files from the PDA to your PC you will want to analyse and print them for your records. TAB separated .TXT file format The tab separated text file format is a common format where ASCII characters are separated into fields by tabs. -
Page 28: Menus And Screens
Menus and Screens Settings menu options Edit Settings menu option (Settings >Edit Settings) SUNSCAN Tab SunScan Emulator: No external SunScan is needed. The software will generate random values as if a SunScan probe is connected. Serial: Select the serial option if you have connected your SunScan to the 9-pin serial port. - Page 29 All: The display is the same as for PAR, but the 64 individual photodiode readings are also stored in the data file. Title A title for your experiment. This is stored along with site details, at the start of a block of readings.
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Page 30: Calibrate Menu Option
Checking the PAR calibration in the Technical reference section for more information. Restore Factory Calibration Restores the calibration of the SunScan sensors that was determined at Delta-T. Review Data menu option Refer to earlier section in user manual “Review Data”. About menu option ... -
Page 31: What To Measure And How
What to Measure and How Experiment Design This section discusses the factors that bear on your experimental objectives. It should help you answer questions like: What equipment do I need? What readings must be taken? Will I have to wait for particular times of day or weather conditions? The type of study you propose to do will determine the time of year and duration of the experiment, and whether you are interested, for example, in monitoring growth by interception of solar radiation, or perhaps in the... - Page 32 Measuring Leaf Area Without a Beam Fraction Sensor This is the most complicated option. For an overview see Take LAI Readings on pages 19 & 20. Each LAI reading below the canopy requires a previous Incident reading and a Beam Fraction reading above the canopy. If measuring LAI without a Beam Fraction Sensor, SunData ensures you first measure Beam Fraction at least once.
- Page 33 the probe. Don't hold the shade too close to the probe - otherwise it will cut out some of the diffuse light as well. SunData looks at the readings from the photodiodes and uses the lowest value to calculate the Diffuse component of the incident light. It uses the highest photodiode values to calculate the incident Total, and uses these two values to calculate and display the Beam Fraction: The Beam Fraction reading is used to increase the accuracy of the...
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Page 34: Canopy Type And Lai Estimates
Canopy type and LAI estimates Some types of canopy do not conform well to the assumptions about canopy structure used by the SunScan in calculating LAI. The following table will give you an initial idea of whether it is applicable to your canopy. You should read the chapter on the LAI theory for a fuller appreciation of the subject. -
Page 35: Preferred Light And Weather Conditions
Preferred light and weather conditions These also will significantly influence your field operations. Limitation Comments Time of day Preferably within 3 hours either side of solar noon depending on the location and season, to meet the next two conditions. Solar zenith angle Measurements are easier when the sun is high. - Page 36 The canopy leaf elements are assumed to be distributed in space in the same directions and proportions as the surface area of an ellipsoid of revolution, symmetrical about the vertical axis. The Leaf Angle Distribution can then be described by a single parameter, the ratio of the Horizontal to Vertical axes of the Ellipsoid.
- Page 37 Setting ELADP The default setting of 1.0 (spherical leaf angle distribution) is a good starting point. If you are unable to estimate the ELADP any other way, set ELADP to 1.0. You can check how much this affects your results in the field by making several measurements in one place within a canopy using different ELADP values, and comparing the LAI values calculated.
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Page 38: Relationship Between Mean Leaf Angle And Eladp
Relationship between Mean Leaf Angle and ELADP Wang & Jarvis (1988) describe the relationship between ELADP and the Mean Leaf Angle, which is sometimes known from other studies. Their results are summarised by the following graph: 0.01 ELADP Typical ELADP Values (from Campbell and van Evert, 1994) Crop ELADP... - Page 39 SunScan Measurement modes Having designed your experiment, choose which data collection option best suites your experiment, and whether you need a BF5 sensor. SunScan has three measurement modes: LAI, PAR or ALL. Each can be used with or without a BF5 connected. If used with a stand-alone analogue data logger, the SunScan Probe acts as a simple line quantum sensor with only one analogue output, representing transmitted PAR.
- Page 40 LAI, PAR and All - measurement modes (Note: the values on the screens below, generated by the Emulator, are for illustration and may not be very realistic). LAI Readings With BFS Without BFS Note: LAI readings are only available in this mode.
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Page 41: Measurement Procedures In The Field
Measurement procedures in the field Check the equipment a day or two before your field experiment for routine matters such as the state of the batteries and the internal desiccant. See the Technical Reference section on page 60 for details of these. Probe handling in the field Levelling the probe The probe is fitted with a miniature bubble level to help... - Page 42 PDA Straps and Belts In use the PDA is always connected to the SunScan via a curly cable, and both your hands are full. Elastic Hand strap An elastic strap provided as standard with each PDA helps secure it in your hand. This and a large pocket, may meet all your needs.
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Page 43: Using The Tripod
Beam Fraction Sensor Handling in the Field The Beam Fraction sensor is definitely recommended for taking most types of readings, however the extra cable connection to the standard SunScan probe does add an unwelcome practical complication! Use of the BF5 radio link may be preferable. Using the tripod The BF5 has a tripod mount, which will probably be the most convenient mounting method to use above low field canopies (up to about 1.8 m... -
Page 44: Par Calibrations
SunScan calibration will be perfectly satisfactory, but if you are working under strong artificial lights (for example) you may need to contact Delta-T for advice. SunScan readings of LAI and fractional interception depend for their... - Page 45 In SunData on the PDA tap the 3 vertical dots on the top right corner of the screen then select Calibrate, Recalibrate SunScan, then follow the instructions. You should not expect to have to do this very often. The photodiodes and light measurement circuits are very stable.
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Page 46: Environmental And Moisture Protection
Environmental and moisture protection You should be aware of the different levels of protection of the components of the SunScan system to avoid putting them at risk when working outdoors. As with all field instruments you should minimise, as far as practical their exposure to high or rapidly changing temperatures. -
Page 47: Lai Theory
LAI theory In this section we shall explain as fully as we can how the SunScan computes its readings of leaf area index, and what the main limitations and provisos are in interpreting these for real canopies. Ingredients of the LAI computation method There are three broad areas contributing to the final result. - Page 48 The relentless advance of computing power has made it possible to model the situation in ways that were not feasible in the past. By integrating the "black leaf" analysis into a computer model Wood has calculated the light levels in the canopy across the whole range of canopy and incident light parameters.
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Page 49: Derivation Of Wood's Sunscan Canopy Analysis Equations
Derivation of Wood’s SunScan canopy analysis equations The major assumptions The canopy is an infinite, uniform, horizontal slab, with leaf elements randomly distributed in proportion to the surface area of an ellipsoid, as described by Campbell. The incident light consists of a component from a point source at a given zenith angle (the Direct beam);... -
Page 50: Transmission Of Diffuse Light
Note: in the following equations derived in MathCAD, different conventions are used for some symbols. Equality is represented by =, and tan (θ) is expressed tan(θ) The extinction coefficient, K, is calculated as follows: tan( ) , x 0.708 1.702 ( 1.12... - Page 51 The next section derives the transmission of light from a uniform overcast sky through a uniform infinite canopy of black leaves of constant LAI with an ellipsoidal leaf angle distribution. Let the sky have uniform brightness of 1 per steradian over the hemisphere.
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Page 52: Modelling The Canopy Transmission
Diffuse light transmission (cosine corrected sensor) Transmission fraction Leaf Angle Distribution Vertical diff ( , 0 L Vertical diff ( , 1 L Spherical diff ( 1000 L Spherical Horizontal 0.01 Horizontal 0.001 Leaf Area Index Modelling the canopy transmission Accounting for incomplete absorption of PAR by the canopy elements, and scattering of light within the canopy is complicated. - Page 53 Of the light intercepted by the leaf element, a fraction a (absorption) is totally absorbed. The remainder is re-emitted uniformly in all directions. In detail: The canopy is divided into horizontal layers of LAI 0.1 Direct beam absorption by each layer is calculated using Campbell's equation.
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Page 54: Accuracy Of Lai Calculations
Accuracy of LAI calculations When used to predict LAI from transmitted fraction, the functions used in the SunData software are accurate to within ±10% ±0.1 over the range of LAI less than 10 and Zenith Angle less than 60° when compared to the output of the full model. -
Page 55: Functions Used To Model Canopy Transmission
Functions used to model canopy transmission Diffuse light - cosine response sensor The transmission of diffuse light through a canopy, as measured by a cosine corrected sensor, can be modelled by the following functions: Given: A ( ) x 1.38 0.15 x 0.007 B ( ) x... - Page 56 This was again calculated numerically and curves fitted to the data with similar accuracy as above. The curves fitted are: Given: P ( ) x 0.4 exp( 0.1 x ( atan( 0.9 x 0.95 Q( ) x 0.255 atan( ) x R( ) x exp( Q( ) x...
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Page 57: Modelling Incomplete Par Absorption And Scattering
Modelling incomplete PAR absorption and scattering Radiation models have been used for many years to calculate the effects of scattering in the canopy e.g. Norman & Jarvis (1975). Wood's model incorporates Campbell’s ellipsoidal leaf angle distribution and the effects this has on transmission of both Direct and Diffuse light. The model splits the canopy into layers of LAI 0.1, extending to a sufficient depth to absorb all of the incident light. -
Page 58: Calculating Zenith Angles
The full equation thus becomes: Direct , x f b exp g dir ( part C( ) x Diffuse A( ) x L a B( ) x L a part This looks hard to invert to get LAI from τ, but an iterative solution is fairly straightforward given the computing power, and is much simpler than the full numerical solution. -
Page 59: Scientific References
Scientific references Campbell G S (1986). Extinction coefficients for radiation in plant canopies using an ellipsoidal inclination angle distribution. Agric. For. Meteor., 36:317-321. Campbell G S and F K van Evert (1994) Light interception by plant canopies: efficiency and architecture. In J L Monteith, R K Scott, and M H Unsworth, Resource Capture by Crops, Nottingham University Press. -
Page 60: Technical Reference
Technical Reference Maintenance Batteries Apart from the PDA, all the components of the SunScan system are powered by alkaline 1.5V AA cells. Do not substitute other types of cell. Checking the batteries The SunScan system requires batteries within the probe, in the PDA, in the BF5 and any BF-RL4 radio link if attached. - Page 61 SunScan Probe SS1-RL4 The probe is powered by 4 x AA cells. These should give about 500 hrs operating time with radio usage. Replace the batteries when the level has fallen near to 5 V (or 4.7 V level for non-radio operation). BF5 radio transmitter BF5-RL4 The transmitter is powered by 4 x AA cells.
- Page 62 Desiccant The SunScan probe, BF5 and BF5-RL4 transmitter module each contain desiccant packs. The desiccant packs must be refreshed from time to time to avoid the possibility of condensation within the instruments. The dryness of the desiccant pack may be indicated by a coloured panel on the instrument.
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Page 63: Checking The Par Calibration
Warning! Do not attempt to change the factory calibration without referring back to Delta-T first. The most likely cause of an apparent change of calibration is physical: dirt or scratching on the BF5 dome, or dirt or staining on the SunScan diffuser. -
Page 64: Troubleshooting
Troubleshooting While running SunData SunData reports “SunScan probe not connected”. Check the cable connections. Check the condition of the batteries in the SunScan probe. Change as a precaution. SunScan or BF5 give inconsistent light readings. Make sure the desiccant condition indicators are blue. ... - Page 65 BF-RL4 Transmitter Check Connect the BF-RL4 to a tested BF5 (without an EXT/8w-xx cable). Check the BF-RL4 antenna is correctly plugged in to the BNC connector. Depress the button to switch on. The BF-RL4 red LED should flash at intervals of 3 seconds.
- Page 66 After a few single flashes, the probe should “lock on” to the transmitted radio signal and simultaneously give a double flash. Observe the magnitude of the PAR light readings displayed on the PDA. Symptom Cause or comment Probe LED gives single Failed to find a transmission.
- Page 67 The procedure below is specific to the USB memory stick connection but the process is similar, regardless of the connection type: First you will need to download the SunData PDA files from our website: https://delta-t.co.uk/product/sunscan/#support SS1 User Manual v3.4 Technical Reference 67...
- Page 68 Once you have downloaded the files transfer them onto your USB memory stick: You then need to plug the USB stick into the PDA so you can run the *.apk file. Note: If it is the first time you have plugged the USB stick into an android device, you may need to format it first (see “USB port”...
- Page 69 NOTE: It can sometimes take a long time for the USB stick to be read and displayed. If the SunData icon is not displayed, remove and re-insert the USB stick. Scroll up and select Go back to step 4. ‘Mass storage’ this is the USB stick.
- Page 70 Wait until After this step remove ‘SunData’ is the USB stick installed. The notification below will appear. 70 Technical Reference SS1 User Manual v3.4...
- Page 71 Press and hold the SunData Icon. Slide up and keep pressed for step 13 Open and then ‘Quit’ SunData to ensure it is installed correctly. SS1 User Manual v3.4 Technical Reference 71...
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Page 72: Problem Reports
Problem Reports It will help considerably if you can send as much relevant detail as possible. In particular: a description of the fault, its symptoms, or error messages what components of the SunScan system you are using details of any PC you are using. -
Page 73: Specifications
Specifications SunScan Probe type SS1 Active area 1000 x 13 mm wide. Sensor spacing 15.6 mm Spectral response 400 - 700 nm (PAR) Measurement time 120 ms 2500 mol.m Maximum reading 0.3 mol.m Resolution Linearity better than 1% Accuracy +/- 10% 1 mV per mol.m Analogue output Serial interface... - Page 74 Refer to PDA user guide for full specifications Android 12 (GMS) Android Enterprise Recommended MediaTek i350, 4 cores 2.0 GHz Memory 4 GB (RAM) / 64 GB (Storage) 4.8″ capacitive multi-touch 720×1280 pixels Display Sunlight readable Glove/rain mode Battery life 17h51m (all RF on) Battery charging 2h21m...
- Page 75 Environmental IP 65 (shower and dust proof) sealing Desiccant pack Activated clay, 60 x 130 mm RS232 connector M12 – 5 way connector Mounting bush ¼ inch Whitworth camera tripod socket Size and weight 125mm x 125mm x 40mm; 450g (excl. antenna) SunScan with Radio Module SS1-RL4 Type SS1-RL4...
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Page 76: Carrying Case
Types EXT/8w-5, EXT/8w-10, EXT/8w-25 Length 5 m, 10 m, 25 m Terminations 5-way M12 male to 5-way M12 female Telescopic Tripod 3-way head with quick release platform. Geared friction elevator control. Locking leg catches and brace. Dual Spike/rubber feet. Type BFT1 Max height 1.73 m... -
Page 77: Par Performance
PAR Performance The graphs below show the actual spectral and cosine response curves for the SunScan system. Spectral response The spectral response curve shows that the SunScan response is almost entirely within the PAR wavelength band of 400 nm - 700 nm. The GaAsP sensors used have an increased sensitivity towards the red end of the spectrum, but this is compensated for by the sharp cut-off at 670 nm. - Page 78 Cosine responses of probe and BF5 The cosine response curves show a diminishing response compared to the ideal at high zenith angles. For this reason, you should avoid taking measurements when the sun is strong and near the horizon. Most studies will be looking at the ratio of incident and transmitted light, and the graph shows the SunScan and Beam Fraction sensor are very closely matched in their cosine and spectral responses, so the small deviations from the ideal will not introduce significant errors.
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Page 79: Logging The Probe As A Linear Quantum Sensor
No Data Collection Terminal is used, but you do require a data logger that can supply power to the probe when taking readings. The Delta-T GP1 and GP2 loggers are suitable for this purpose. -
Page 80: Logging The Beam Fraction Sensor
Logger requirements The probe requires a voltage supply of 7-15 V dc (unregulated), at about 30 mA current. The analogue output is enabled when the external voltage is greater than the battery voltage. Configure one channel of the logger for voltage input, with the above sensitivity. - Page 81 Glossary Beam fraction - the fraction of the Total incident PAR in the Direct beam. Beam Fraction Sensor - The BF5 consists of an array of 7 photodiodes under a specially shaped shadow mask, used for measuring Direct and Diffuse light above the canopy. Beer’s law - a general law describing transmission through an absorbing medium.
- Page 82 by a single parameter, the Ellipsoidal Leaf Angle Distribution Parameter (ELADP), which is the ratio of the horizontal to vertical axes of the ellipsoid. An ELADP much greater than 1 describes a canopy of mostly horizontal leaves, an ELADP near 0 describes a canopy of mainly vertical leaves.
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Page 83: Technical Support
Delta-T shall not be liable to the buyer by reason of any delay or failure to perform their obligations in relation to the goods and/or services if the delay or failure was due to any cause beyond the Delta-T’s reasonable... -
Page 84: Service And Spares
No goods or equipment should be returned to Delta-T without first obtaining the return authorisation from Delta-T or our distributor. On receipt of the goods at Delta-T you will be given a reference number. Always refer to this reference number in any subsequent correspondence. - Page 85 Index Absorption ..........35 data files ........27; display Accuracy ........43, 44, 73 ............27 All data..........22 Data Files ..........26 Antenna ......14, 15, 65, 66, 75 Data.txt ..........26 Batteries .... 11, 12, 60, 62, 64, 65, 66 D-connector ........
- Page 86 Local time ..........82 Relocating the BF3 ........7 logger cable ........... 10 Review Data .......... 22 Logger requirements ......80 RS232 cable ........64, 65 Logging ..........79 Sampling volume ........34 Maintenance ......11, 12, 60 Service ..........84 mapping ..........
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