Decagon Devices AccuPAR LP-80 Operator's Manual
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Decagon Devices AccuPAR LP-80 Operator's Manual

Par/lai ceptometer
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AccuPAR
PAR/LAI ceptometer
model LP-80
Operator's Manual
Version 10
Decagon Devices, Inc.

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  • Page 1 AccuPAR PAR/LAI ceptometer model LP-80 Operator’s Manual Version 10 Decagon Devices, Inc.
  • Page 2 Decagon Devices, Inc. 2365 NE Hopkins Court Pullman, WA 99163 tel: (509) 332-2756 fax: (509) 332-5158 www.decagon.com Trademarks AccuPAR and Ceptometer are registered trademarks of Decagon Devices, Inc. © 2006-2010...

  • Page 3: Table Of Contents

    AccuPAR LP-80 Table of Contents Table of Contents 1. Introduction ....1 Customer Service and Tech Support ..1 Warranty .
  • Page 4 AccuPAR LP-80 Table of Contents 5. Log Menu ....19 6. Data Menu ....21 View .
  • Page 5 AccuPAR LP-80 Table of Contents 11. Care and Maintenance ..73 Batteries .......73 Cleaning the Probe and Controller .

  • Page 6: Introduction

    AccuPAR LP-80 1. Introduction 1. Introduction Welcome to Decagon’s AccuPAR model LP-80 PAR/LAI Ceptometer. The AccuPAR measures Photosynthetically Active Radiation (PAR) and can invert these readings to give you Leaf Area Index for your plant canopy. This manual is designed to help you accomplish your research goals, and understand how to get the most out of your AccuPAR.

  • Page 7: Warranty

    AccuPAR LP-80 1. Introduction Warranty The AccuPAR has a one year warranty on parts and labor. It is activated upon the arrival of the instrument at your location. Seller’s Liability Seller warrants new equipment of its own manufacture against defective workmanship and materials for a period of one year...

  • Page 8: Repair Instructions

    AccuPAR LP-80 1. Introduction Repair Instructions If your AccuPAR needs to be sent in for service or repair, call Decagon at (509) 332-2756 or 1-800-755-2751 (US and Canada). We will ask you for your address, phone number, and serial number. For non-warranty repairs, we will also ask for a purchase order number, a repair budget, and billing address.

  • Page 9: About The Lp-80

    AccuPAR LP-80 2. About the LP-80 2. About the LP-80 The AccuPAR model LP-80 is a menu-driven, battery- operated linear PAR ceptometer, used to measure light interception in plant canopies, and to calculate Leaf Area Index (LAI). It consists of an integrated microprocessor- driven datalogger and probe.

  • Page 10: Overview Of The Lp-80

    AccuPAR LP-80 2. About the LP-80 Minimum Spatial resolution: 1cm Data Storage Capacity: 1MB Flash Unattended logging interval: User selectable, between 1 and 60 minutes. Instrument weight (w/batteries): 0.55 kg (1.21 lbs) Data retrieval: direct via RS-232 Keypad: 7-Key menu-driven.

  • Page 11: Components Of The Lp-80 System

    AccuPAR LP-80 2. About the LP-80 Components of the LP-80 system The AccuPAR and its accessories come to you in a durable foam-padded carrying case. As you open the case, you should find the following: • AccuPAR model LP-80 •...

  • Page 12: Keyboard Operation

    AccuPAR LP-80 2. About the LP-80 Keyboard Operation Figure 1: LP-80 Keypad The LP-80’s keypad is a 7-key panel, designed for ease of use and intuitive navigability through the operating system. Here is a brief description of the key functions:...

  • Page 13: Turning On The Instrument

    AccuPAR LP-80 2. About the LP-80 ON/OFF Key: Located in the upper left corner, it turns the instrument on or off. The AccuPAR will turn itself off automatically after 10 minutes of inactivity. MENU Key: Cycles between the four menus.
  • Page 14 AccuPAR LP-80 2. About the LP-80 displayed in the center portion of the screen. If you have the external PAR sensor connected, you will also see its real-time PAR data. current time menu tabs low battery indicator At any time, you can cycle between the four menus by pressing the MENU key.

  • Page 15: Definitions

    AccuPAR LP-80 3. Definitions 3. Definitions The AccuPAR LP-80 uses several variables to calculate Leaf Area Index, and displays values for these variables on the screen as measurements are taken. This chapter will discuss these variables and their definitions. If you’re not familiar with them, we recommend that you review this chapter before proceeding with measurements.

  • Page 16: Tau (T)

    AccuPAR LP-80 3. Definitions along the probe.  Tau ( Tau is another variable in the LAI inversion equations. It is defined as the ratio of below canopy PAR measurements to the most recent above canopy PAR value. It is measured automatically by the instrument, based upon the PAR readings you make.

  • Page 17: Zenith Angle (Z)

    AccuPAR LP-80 3. Definitions multiple PAR measurements under the canopy in variable light conditions without having to keep moving the instrument in and out of the canopy to update the above canopy PAR reference. The external sensor is also the PAR standard to which the wand is calibrated.

  • Page 18: Leaf Distribution Parameter (X)

    AccuPAR LP-80 3. Definitions displayed and updated at the bottom of the screen in the PAR menu. Leaf Distribution Parameter (x) Leaf Distribution Parameter (also known as Chi, or x) refers to the distribution of leaf angles within a canopy. The...
  • Page 19 AccuPAR LP-80 3. Definitions Table 1: typical x values Crop Ryegrass 0.67 to 2.47 Maize 0.76 to 2.52 0.80 to 1.27 Wheat 0.96 Barley 1.20 Timothy 1.13 Sorghum 1.43 Lucerne 1.54 Hybrid Swede 1.29 to 1.81 Sugar Beet 1.46 to 1.88 Rape 1.92 to 2.13...

  • Page 20: Par/Lai Menu

    AccuPAR LP-80 4. PAR/LAI Menu 4. PAR/LAI Menu The first menu option is the PAR/LAI sampling menu, which is used for measurements with the AccuPAR. The default screen is one similar to this: This screen example indicates that the current real-time PAR level is 2 mols/m...
  • Page 21 AccuPAR LP-80 4. PAR/LAI Menu canopy PAR reading. Other relevant data are displayed at the bottom of the screen, as shown in this example: Average above and below Active Par Readings reading indicator Number of taken readings Real time above and...
  • Page 22 AccuPAR LP-80 4. PAR/LAI Menu have been made, so the average of the four above-canopy PAR values is 211 mols, while the average of the three below- canopy values is 20 mols. Note: When the external sensor is connected, readings from the external sensor are used as above PAR readings to calculate LAI.
  • Page 23 AccuPAR LP-80 4. PAR/LAI Menu name or description, e.g. “Plot 1”. Selecting “Annotate” will cause the following screen to appear: You will see a series of lines, with a set of arrows above and below the first. If you have annotated a previous reading, the old annotation will remain to be changed or deleted.

  • Page 24: Log Menu

    AccuPAR LP-80 5. Log Menu 5. Log Menu When you advance to the LOG menu, the following screen appears: This menu allows you to put the instrument in an unattended par datalogging mode. In this mode, the AccuPAR will automatically measure and store PAR data at an interval that you specify.
  • Page 25 AccuPAR LP-80 5. Log Menu will change to the following: The data that are taken in this mode will be stored automatically without annotation to memory. Note: You can move from this menu to other menus while the logging mode is activated. While activated, the LP-80 continues to log data whether or not the AccuPAR’s display is on or if you are in a different...

  • Page 26: Data Menu

    AccuPAR LP-80 6. Data Menu 6. Data Menu The Data menu allows you to view, download, and erase the data that you store with your AccuPAR. When you advance to this menu, the following screen appears: # of Summary Records...

  • Page 27: Download

    AccuPAR LP-80 6. Data Menu You can scroll between different readings using the up and down arrows. To view detailed data from a selected record, press the ENTER key while it is highlighted. The stored data will be displayed. Annotation...
  • Page 28 AccuPAR LP-80 6. Data Menu Downloading using Windows Hyperterminal Listed below are the steps involved for downloading using Windows Hyperterminal, which comes with Windows XP and earlier Windows operating systems. (For newer operating systems such as Windows Vista and Windows 7, a third party terminal program will need to be used.)
  • Page 29 AccuPAR LP-80 6. Data Menu 5. Once the terminal window opens, click on the File menu and select “Properties.” Click on the “Settings” tab, and then click on the “ASCII Setup” button. Check the box that says “Append line feeds to incoming line ends,” and also “Wrap lines that exceed terminal width,”...
  • Page 30 AccuPAR LP-80 6. Data Menu Description of Outputs: Above/Below Records Item Description The Record ID is a unique identifier for each record. RID’s are store sequentially in memory and can be used for downloading data. Type “ABV” or “BLW” – which is used to identify the data record type.
  • Page 31 AccuPAR LP-80 6. Data Menu Summary Record Contents Item Description The Record ID is a unique identifier for each record. RID’s are store sequentially in memory and can be used for keeping track of downloaded data. Type “SUM” – which is used to identify the data record type.

  • Page 32: Erase

    AccuPAR LP-80 6. Data Menu The leaf distribution parameter Chi or x is the Chi (x) ratio of projected area of an average canopy element on a horizontal plane to its projection on a vertical plane. The Beam Fraction is the ratio of direct beam radiation coming directly from the sun to radiation coming from all ambient sources.

  • Page 33: Utility Software

    AccuPAR LP-80 7. LP-80 Utility Software 7. LP-80 Utility Software The AccuPar LP-80 comes with the LP-80 Utility software which allows you to download stored data to your computer via the RS-232 cable that came with your system. Downloading Data To download data, follow these steps: 1.
  • Page 34 AccuPAR LP-80 7. LP-80 Utility Software 6. The "Save LP-80 Data" dialog box will appear: 7. Name your file, and choose a format to save it in, and click Save. (For more information, see Data File Formats.) 8. A progress bar will appear on the main screen.
  • Page 35 AccuPAR LP-80 7. LP-80 Utility Software Data Organization Data from the LP-80 is saved into several columns. A. Record Type--The data record type (SUM, ABV, or BLW). B. Date and Time Measurement-- date/time when the reading was taken. C. Annotation--The annotation is a string that a user may use to identify the reading.

  • Page 36: Erasing Data

    AccuPAR LP-80 7. LP-80 Utility Software K. Latitude--Latitude location in degrees. L. Longitude--Longitude location in degrees. M. Segment 1-8 PAR--Individual PAR readings from each of the 8 segments. N. External Sensor PAR--PAR reading from the External Sensor. O. Record ID--The Record ID is a unique identifier for each record.

  • Page 37: Setting The Date And Time

    AccuPAR LP-80 7. LP-80 Utility Software been removed from your LP-80. Setting the Date and Time You can use the LP-80 Utility to easily set your device’s date and time: 1. Make sure the LP-80 is properly connected to your computer.

  • Page 38: The Preferences Menu

    AccuPAR LP-80 7. LP-80 Utility Software • Firmware version (the software that runs your LP-80) • Firmware checksum status • Battery level • Number of stored readings • Current date and time as set in your LP-80 On this screen you can also set the time.
  • Page 39 AccuPAR LP-80 7. LP-80 Utility Software and time for downloaded readings use the formatting of the Windows Regional and Language Options (accessible in the Windows Control Panel). You can set the formatting to use a day/month/year format with 12- or 24-hour time.

  • Page 40: Software And Firmware Updates

    AccuPAR LP-80 7. LP-80 Utility Software Application Tab: • Automatic Internet Version Check: If this checkbox is selected, the program will automatically check for updates as soon as it starts (only if you are connected to the Internet). • Automatic Clock Synchronization: Keeps the LP-80’s clock synchronized to the time on your computer.

  • Page 41: Config Menu

    AccuPAR LP-80 8. Config Menu 8. Config Menu The Config menu is where you configure and set most of the parameters that affect the functionality of your AccuPAR. When you scroll to this menu, the following screen appears: Scrolling further down: And further down: Use the up and down arrows to scroll thru the menu items.
  • Page 42 AccuPAR LP-80 8. Config Menu Calibration The LP-80 is equipped with a calibrated external PAR sensor. As mentioned earlier, this is used for making simultaneous above and below canopy PAR measurements. It is also used to calibrate your AccuPAR’s probe, ensuring that the PAR response between the external sensor and the probe are the same.
  • Page 43 AccuPAR LP-80 8. Config Menu When you have the instrument ready to calibrate, move out of the probe area to minimize reflection off your body, and press the ENTER button to perform the calibration (it is important not to affect light levels on the probe through shading or reflection).
  • Page 44 AccuPAR LP-80 8. Config Menu configured location. Highlight the item you would like to change and press ENTER. In the next screen, use the up and down arrows to change it and then press enter to save the change. To exit the location menu, press MENU or ESC.
  • Page 45 AccuPAR LP-80 8. Config Menu Leaf Distribution ( x) This menu is used to set the x (leaf distribution) parameter for the plant canopy you plan to measure. See the next chapter for further explanation of the x parameter. To change the value of the x parameter, use the up and down arrow keys.
  • Page 46 AccuPAR LP-80 8. Config Menu calibration between the two sensors. Active Segments For some measurement purposes, you may not want to use the entire length of the probe. For such applications, you can turn off sections of the probe, starting from the base and continuing down the probe to the end.
  • Page 47 AccuPAR LP-80 8. Config Menu significant amount of noise to the AccuPAP LP80’s sensor measurements. The power filter setting is designed to eliminate this electrical noise that comes from the AC powered light source. You should set the value of the Power Noise Filter to match the frequency of the power where you live.

  • Page 48: Par And Lai Theory

    AccuPAR LP-80 9. PAR and LAI Theory 9. PAR and LAI Theory The AccuPAR is useful for a number of applications, including the measurement of average and intercepted PAR. From these measurements, LAI can be calculated and other attributes of the canopy structure can be determined.
  • Page 49 AccuPAR LP-80 9. PAR and LAI Theory where P is the amount of dry matter produced, S is the flux density of incident radiation intercepted by the crop, f is the fraction of incident radiation intercepted by the crop, and e is a conversion efficiency.
  • Page 50 AccuPAR LP-80 9. PAR and LAI Theory  t – (equation 3) The error resulting from this approximation is usually small when t, r, and r are measured in the PAR waveband because most of the PAR is absorbed by a closed canopy. The error...
  • Page 51 AccuPAR LP-80 9. PAR and LAI Theory accurate for making measurements of intercepted radiation. However, measurement of the other terms needed for equation 2 is simple and will also be explained. Sampling for Fractional Interception The functions needed to perform these calculations are available in the PAR sampling menu of the AccuPAR.
  • Page 52 AccuPAR LP-80 9. PAR and LAI Theory up-arrow key. The reading displayed in the upper right portion of the screen is the value for S. Measure T by placing the AccuPAR below the plant canopy, being careful to place it below all of the leaves. Try to keep the instrument level.
  • Page 53 AccuPAR LP-80 9. PAR and LAI Theory the  value will be updated. After you have taken sufficient measurements, use the displayed  value in the lower left corner for t (see equation 6). To find r, level the AccuPAR above the canopy and press the up-arrow.

  • Page 54: Using Par To Determine Leaf Area Index

    AccuPAR LP-80 9. PAR and LAI Theory Using PAR to determine Leaf Area Index The PAR measured by the AccuPAR within a plant canopy is a combination of radiation transmitted through the canopy and radiation scattered by leaves within the canopy. A complete...
  • Page 55 AccuPAR LP-80 9. PAR and LAI Theory  -------------------------------------------------------------- - – 0.733   1.744 x 1.182 (equation 12) where  is the zenith angle of the sun and x is a leaf angle distribution parameter (see Chpt. 3 for definition). When x=1,...
  • Page 56 AccuPAR LP-80 9. PAR and LAI Theory equations is smaller than other uncertainties in the method, so equation 14 is used in the LP-80 to determine LAI. Inverting equation 14 gives the following:   f  – ------ - –...

  • Page 57: Extinction Coefficient & Canopy Structure

    AccuPAR LP-80 9. PAR and LAI Theory The next example uses measurements on a sunny day. 1614 mol was measured above a pea canopy and 80 mol under the canopy. The fraction of PAR transmitted by the canopy was therefore  = 80/1614 = 0.05. The solar zenith angle was 30°, and the beam fraction was 0.881.
  • Page 58 AccuPAR LP-80 9. PAR and LAI Theory parameter, , is the zenith angle (angle measured from the vertical) of the probe or solar beam.  usually varies with zenith angle. The transmission coefficient for a canopy of randomly placed elements is: ...
  • Page 59 AccuPAR LP-80 9. PAR and LAI Theory more discussion of x and typical values for some canopies. 1000 Zenith Angle, Degrees Figure 1: Extinction Coefficient vs. Zenith Angle Figure 1 shows the extinction coefficient plotted as a function of zenith angle for various values of x. There are two important things to note.
  • Page 60 AccuPAR LP-80 9. PAR and LAI Theory    – (equation 18) If a measurement is made when the zenith angle is about 57°, equation 18 can be used directly to find L.  If measurements of the transmission coefficient,...
  • Page 61 AccuPAR LP-80 9. PAR and LAI Theory Linear Regression gives: A = 1.21 B = 0.12 L = 2(1.21 + 0.12) = 2.64 x = exp(-0.12 / 0.4 x 2.64) = 0.9 A more precise method for finding x is as follows. We would like to find values for x and L which minimize: ...
  • Page 62 AccuPAR LP-80 9. PAR and LAI Theory   ( ( (equation 22) We can calculate p from equation 17: -- -      --------------------------------------      (equation 23) If  = 0, -- - ...
  • Page 63 AccuPAR LP-80 9. PAR and LAI Theory  0.79 (0) = 0.21 = 0.29  Cover = 1 - (0) = 1 - 0.29 = 0.71 Intercepted radiation averaged over an entire day can be estimated from:  f = 1- (equation 24) ...
  • Page 64 AccuPAR LP-80 9. PAR and LAI Theory The next table shows typical values. Table 3: values of u and v for equation 25 0.69 0.73 0.75 0.82 0.81 0.89 0.90 0.95 0.96 0.98 0.99 0.99 Combining equations 16 and 25 gives: ...

  • Page 65: Lai Measurements & Non-Random Distribution

    AccuPAR LP-80 9. PAR and LAI Theory -- -     1.14 ------------------------------------------------------------------------ --------- - 0.59 – 0.733 1.94   1.774 0.9 1.182 -0.13 q = 0.80 x 2.64 /0.59 = 1.2  = 0.21 = 0.15 ...
  • Page 66 AccuPAR LP-80 9. PAR and LAI Theory the actual orientation of the canopy elements relating to the interception of PAR at a given angle. In situ measurements of LAI using hemispherical photography were equated with this new term “effective plant area index” (L ), which was defined L...
  • Page 67 AccuPAR LP-80 9. PAR and LAI Theory accurate portrayal of the canopy’s structure and orientation with respect to light interception. In this instance, while clumping effects within the canopy remain present, these effects do not cause error with regard to light interception and the effective area index for that situation.
  • Page 68 AccuPAR LP-80 9. PAR and LAI Theory Figur e 2: Randomly Dispersed L= L Figure 3: Under dispersed L> L Figure 4: Over dispersed L< L...

  • Page 69: Zenith Angle And Equation Of Time

    AccuPAR LP-80 9. PAR and LAI Theory Zenith Angle and Equation of Time The formulas for calculating elevation angle are relatively straightforward. The zenith angle is calculated from: = arccos(sinLsinD+cosLcosDcos0.2618(t-t (equation 30) where L is the latitude, D is the solar declination, t is the time, and t is the time of solar noon.
  • Page 70 AccuPAR LP-80 9. PAR and LAI Theory where LC is the longitude correction and ET is the Equation of Time. LC is +4 minutes, or +1/15 hour for each degree east of the standard meridian and -1/15 hour for each degree west of the standard meridian.
  • Page 71 AccuPAR LP-80 9. PAR and LAI Theory The standard meridian for Pullman is 120°. The local meridian is 2.8° east of the standard meridian, so LC = 2.8/15 = 0.19 hours. From Equation 33 or Table 4, ET = -0.06 hours. Equation 32 then gives t = 12 - 0.19 - (-0.06) = 11.87.
  • Page 72 AccuPAR LP-80 9. PAR and LAI Theory Table 4: Solar Declination and Equation of Time Date Day of Year D in radians ET hour Jan 1 -0.403 -0.057 Jan 10 -0.386 -0.123 Jan 20 -0.355 -0.182 Jan 30 -0.312 -0.222 Feb 9 -0.261...
  • Page 73 AccuPAR LP-80 9. PAR and LAI Theory Table 4: Solar Declination and Equation of Time Date Day of Year D in radians ET hour Aug 18 0.233 -0.065 Aug 28 0.174 -0.022 Sep 7 0.111 0.031 Sep 17 0.045 0.089 Sep 27 -0.023...

  • Page 74: Measurement Tips

    AccuPAR LP-80 10. Measurement Tips 10. Measurement Tips Above Canopy (External) Sensor The AccuPAR is supplied with an external PAR sensor which connects to the port on the right side of the AccuPAR. The external sensor allows you to take simultaneous above and below canopy PAR readings without having to move the instrument above and below the canopy you are measuring.

  • Page 75: Sample Size

    AccuPAR LP-80 10. Measurement Tips 2. You can use your AccuPAR as an above-canopy reference by regularly collecting above-canopy PAR data in a large clearing within the canopy structure. Sample Size When evaluating experimental protocols for measuring average intercepted PAR and determining average LAI for a large area, make sure that a sufficient number of samples and sampling locations are used.
  • Page 76 AccuPAR LP-80 10. Measurement Tips representation of the entire below-canopy PAR environment both under the plants and between rows. We suggest a sampling regime such as shown below, where the probe either extends from mid-row to mid-row, or extends from mid-row to the middle of the open space between rows, depending on row width and canopy size.
  • Page 77 AccuPAR LP-80 10. Measurement Tips Mid-line of open space between rows Scenario 2: The base of the probe is in the center of the row, while the end is in the center of the open space between rows. When sampling the next row, the same orientation is maintained, giving an accurate representation of the overall area.

  • Page 78: Care And Maintenance

    AccuPAR LP-80 11. Care and Maintenance 11. Care and Maintenance Batteries The AccuPAR uses four standard 1.5V AAA alkaline batteries. These batteries are easily obtained and should last for at least 2 years before they have discharged. If a battery icon appears in...

  • Page 79: Re-Calibration

    AccuPAR LP-80 11. Care and Maintenance accurate readings. To clean the probe, use a small amount of isopropyl alcohol and a soft cloth. Rub the surface until it is clean. To clean the controller, use a soft cloth and water to wash heavy dirt, then use ethyl or isopropyl alcohol to finish cleaning.
  • Page 80 AccuPAR LP-80 11. Care and Maintenance decline if there is any debris on the probe which prevents light from entering the sensors. • Although the AccuPAR is splash-resistant, don't immerse the instrument in water, or leave the it in contact with rain for long periods of time.

  • Page 81: Declaration Of Conformity

    2003 This is to certify that the AccuPAR model LP-80, manufac- tured by Decagon Devices, Inc., a corporation based in Pull- man, Washington, USA meets or exceeds the standards for CE compliance as per the Council Directives noted above. All instruments are built at the factory at Decagon and pertinent testing documentation is freely available for verification.

  • Page 82: Appendix A: External Sensor Information

    AccuPAR LP-80 Appendix A: External Sensor Information Appendix A: External Sensor Information The external quantum sensor provided with the AccuPAR model LP-80 is the Apogee SQ110. It is calibrated to provide an output of 5 mol m per mV. This sensor offers good accuracy, however you should be aware of potential sources of error.

  • Page 83: Cosine Response

    AccuPAR LP-80 Appendix A: External Sensor Information underestimates the 400 to 500 nm wavelengths (blue light), matches in the 550-650 nm wavelengths (yellow and orange), and has little sensitivity above 650 nm (red light). Fortunately common light sources are mixtures of colors and many spectral errors offset each other.

  • Page 84: Appendix B: Troubleshooting

    AccuPAR LP-80 Appendix B: Troubleshooting Appendix B: Troubleshooting The AccuPAR LP-80 is a high performance, low maintenance instrument, designed to have few problems if used with care. Unfortunately, sometimes even the best operators using the best instruments encounter technical difficulties. Below is quick reference guide that will direct you to detailed solutions of some problems that may occur.
  • Page 85 AccuPAR LP-80 Appendix B: Troubleshooting Troubleshooting Quick Guide (continued) If this problem occurs: Refer to: Only one mode can be run at a time message. . . Problem #10 Memory full message ..... . Problem #11 No summary data message.
  • Page 86 AccuPAR LP-80 Appendix B: Troubleshooting Message on screen displays the following: SOLUTION: The external sensor must be reading a PAR value of 600µmol/ m²s in order to calibrate. Make sure that the external is attached and is in full view of the Sun. If the day is overcast, wait to calibration the sensor on a sunny day when PAR levels are above 600µmol/m²s.
  • Page 87 AccuPAR LP-80 Appendix B: Troubleshooting battery holder and cycle the power on the instrument. 5. PROBLEM: Message on screen displays the following: SOLUTION: After changing the batteries or loading new firmware onto an instrument, this message may appear. Navigate to the configuration menu and verify that the date and time are set properly.
  • Page 88 AccuPAR LP-80 Appendix B: Troubleshooting batteries and then press ENTER when powered back on to exit this screen. 7. PROBLEM: Message on screen displays the following: SOLUTION: The instrument cannot download new firmware updates. To down-load new firmware to the LP-80, or to stop this message from displaying, the instrument must be serviced by Decagon.
  • Page 89 AccuPAR LP-80 Appendix B: Troubleshooting LP80 is user-upgradeable.) To obtain this, visit Decagon's website to see if new updates are available; if not, contact Decagon for the newest firmware version. Note: You will lose any saved data records when you install the new firmware.
  • Page 90 AccuPAR LP-80 Appendix B: Troubleshooting 10. PROBLEM: Message on screen displays the following: (May also happen on the log menu) SOLUTION: Only one mode may be running at a time. If you are logging, this message will appear on the PAR screen. If you are taking a reading on the PAR screen, a message similar to this will appear in the Log menu.
  • Page 91 AccuPAR LP-80 Appendix B: Troubleshooting SOLUTION: This message indicates that the data memory is full. You may ontinue to view the real-time PAR values, configuration settings, and previously stored data while the memory is full. No more data records can be saved until the data records stored in memory are downloaded to the computer and erased from the LP-80.
  • Page 92 AccuPAR LP-80 Appendix B: Troubleshooting 13. PROBLEM: Message on screen displays the following: SOLUTION: If you are trying to change a country or city location and you have custom configured the longitude, latitude or UTC offset, this message will appear. If you continue it will reset the location information to the default settings for that city.
  • Page 93 AccuPAR LP-80 Appendix B: Troubleshooting 15. PROBLEM: Downloading data stops in the middle with an error message saying the Utility lost connection with the LP80. SOLUTION: A noisy serial connection can disrupt the connection between the Utility and the LP80. If this error happens regularly, you can try setting your baud rate lower or increasing the number of times a command is sent to the LP80.

  • Page 94: Appendix C: Further Readings

    AccuPAR LP-80 Appendix C: Further Readings Appendix C: Further Readings The following is a list of references that offer more detail concerning plant canopy characteristics and research. Anderson, M.C. (1971) Radiation and crop structure. In Plant Photosynthetic Production, Manual of Methods (eds A.
  • Page 95 AccuPAR LP-80 Appendix C: Further Readings Campbell, G.S., and J.M Norman. (1988) The description and measurement of plant canopy structure. in Plant Canopies: Their Growth, Form and Function (ed. G. Russell), Society for Experimental Biology, Seminar Series 29, Cambridge University Press, New York.
  • Page 96 AccuPAR LP-80 Appendix C: Further Readings corn, sorghum, soybean, and sunflower. Agronomy Journal (1995) Goudriaan, J. (1977) Crop Micrometeorology: A Simulation Study, Center for Agriculture Publication Documentation, Wageningen, The Netherlands. Goudriaan, J. (1988) The bare bones of leaf angle distribution in radiation models for canopy photosynthesis and energy exchange.
  • Page 97 AccuPAR LP-80 Appendix C: Further Readings diverse C4 Grasses. Biomass and Bioenergy. 17:95-112. Kiniry, J.R., J.A. Landivar, M. Witt, T.J. Gerik, J. Cavero, and L.J. Wade. Radiation-use efficiency response to vapor pressure deficit for maize and sorghum. European Journal of Agronomy Oct. 1995.
  • Page 98 AccuPAR LP-80 Appendix C: Further Readings needles branches plants, light transmittance. Agric. For. Meteorol., 54: (in press). Lang, A.R.G., R.E. McMurtrie, and M.L. Benson. (1991) Validity of leaf area indices of Pinus radiata forests estimated from transmittances of the sun’s beam.
  • Page 99 AccuPAR LP-80 Appendix C: Further Readings Maas, S. Cotton canopy structure, light absorption, and growth in the San Joaquin Valley of California. Proceedings of the 1996 Beltwide Cotton Conferences,(2) 1235-1237. Martens, Scott N., S.L. Ustin and R.A. Rousseau. Estimation of tree canopy leaf area index by gap fraction analysis.
  • Page 100 AccuPAR LP-80 Appendix C: Further Readings array of canopies. Agron. J., 75:481-488. Norman, J. M., S.G. Perry, A.B. Fraser, and W. Mach. (1979) Remote sensing of canopy structure. Proc. 14th Conf. Agric. For. Meteor., p.184-185, Am. Meteor. Soc., Boston. Welles, Jon M., and Shabtai Cohen. Canopy Structure...

  • Page 101: Index

    AccuPAR LP-80 Index Index About menu 42 Accessories 6 Batteries replacing 73 type 73 Beam fraction 12 Biomass production 60 Calibration 74 external sensor 40 Canopy distribution 53 Canopy elements non-random distribution 60 Canopy structure error reduction 70 Care 73...
  • Page 102 AccuPAR LP-80 Index Data Menu 21 Date setting 39 setting with LP-80 Utility 32 Declaration of Conformity 76 Delete 27 Downloading setting options for 37 Downloading data 22 with LP-80 Utility 28 Dry matter production 43 E-mail address 1 Erasing files 27...
  • Page 103 AccuPAR LP-80 Index Fractional interception 46 Geographical location setting 38, 40 Intercepted PAR 52 K (extinction coefficient) 53 Keyboard 7 equation for calculating 51 LAI calculation examples 51 Leaf angle distribution 53, 54 Leaf distribution random 52 Leaf distribution parameter 13, 50, 52, 53...
  • Page 104 AccuPAR LP-80 Index and dry matter production 43 definition 10, 43 for LAI 61 PAR/LAI sampling menu 15 Partitioning probe 41 Recalibration 74 References 89 Repair costs 3 instructions 3 Row crops 60 Sample size 70 Segment mode icon 41 Seller’s liability 2...
  • Page 105 AccuPAR LP-80 Index setting 39 setting with LP-80 Utility 32 Viewing stored data 21 Warranty 2 X parameter setting 40 X(leaf distribution parameter) 13, 50, 53 Zenith angle 50 defined 12 equation 64 example calculation 65 setting location for 38, 40...

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