Decagon Devices AccuPAR LP-80, Operator'S Manual

Page 1: ...AccuPAR PAR LAI Ceptometer Model LP 80 Operator s Manual Decagon Devices Inc Version December 13 2013 08 29 36...

Page 2: ...NE Hopkins Court Pullman WA 99163 Phone 509 332 5600 Fax 509 332 5158 Website www decagon com Email support decagon com or sales decagon com Trademarks AccuPAR and Ceptometer are registered trademarks...

Page 3: ...4 PAR LAI Menu 12 4 1 Taking Measurements 12 4 2 Saving and Annotating Readings 14 5 Log Menu 15 6 Data Menu 17 6 1 View 17 6 2 Download 18 6 3 Description of Outputs 20 6 4 Erase 22 7 LP 80 Utility S...

Page 4: ...5 9 6 LAI measurements Non Random Distribution 47 9 7 Zenith Angle and Equation of Time 49 10 Measurement Tips 53 10 1 Above Canopy External Sensor 53 10 2 Sample Size 53 10 3 Clumping in Canopies 54...

Page 5: ...n has Cus tomer Service Representatives available to speak with you Monday through Friday between 7am and 5pm Pacific time Note If you purchased your AccuPAR LP 80 through a distribu tor please contac...

Page 6: ...he factory where originally manufactured Material and equipment covered hereby which is not manufactured by Seller shall be covered only by the warranty of its manufacturer Seller shall not be liable...

Page 7: ...f micro mols per meter squared per second mol m 2s 1 The instrument is capable of hand held or unattended measurement 2 1 AccuPAR LP 80 Instrument Specifications Operating Environment 0 to 50 C 32 122...

Page 8: ...using the up and down arrow keys and the ENTER or ESC keys The AccuPAR can be operated in environments with temperatures from 0 to 50 C and in relative humidities of up to 100 The instru ment ships wi...

Page 9: ...AccuPAR LP 80 2 ABOUT THE LP 80 Figure 1 Product Features Figure 2 LP 80 Keypad 5...

Page 10: ...lues in sub menus Round Green Key The circular key in the upper right corner of the keypad by the AccuPAR logo also serves the same function as the Down arrow key It is designed as an ergonomic altern...

Page 11: ...menus by pressing the MENU key The menus are indicated by the tabs on the top of the screen with the active menu in the foreground If the battery is low a low battery indicator will appear to the righ...

Page 12: ...The AccuPAR measures PAR either manually or in unattended log ging mode Intercepted PAR data can be used for determining im portant parameters of canopy structure and for the calculation of LAI An ex...

Page 13: ...easure ments This is useful if you want to be able to make multiple PAR measurements under the canopy in variable light conditions without having to keep moving the instrument in and out of the canopy...

Page 14: ...n a canopy The parameter is the ratio of the length of the horizontal to the vertical axis of the spheroid described by the leaf angle distribution of a canopy It can also be measured as the ratio of...

Page 15: ...6 to 2 52 Cucumber 2 17 Rye 0 80 to 1 27 Tobacco 1 29 to 2 22 Wheat 0 96 Potato 1 70 to 2 47 Barley 1 20 Horse Bean 1 81 to 2 17 Timothy 1 13 Sunflower 1 81 to 2 31 Sorghum 1 43 White Clover 2 47 to 3...

Page 16: ...by the external sensor will be also displayed above the real time light bar PAR data 4 1 Taking Measurements To make an above canopy PAR measurement press the up arrow key in this menu The resulting v...

Page 17: ...hapter 3 Definitions or chapter 8 Theory for a more detailed description of these variables and their definitions With each above or below canopy measurement a number appears to the right of the PAR v...

Page 18: ...return to the main screen and start over with a new reading 3 Select Annotate and press ENTER to give your data a file name or description e g Plot 1 Selecting Annotate will cause the Annotate screen...

Page 19: ...dom locations instead of leaving the LP 80 in one place and collecting data in log mode You can select the measurement interval by pressing the up or down arrows This will allow you to select any valu...

Page 20: ...ted While activated the LP 80 continues to log data whether or not the AccuPAR display is on or if you are in a different menu Caution This mode is for short term experiments one or two days We did no...

Page 21: ...sis or erase the data memory from the Data screen To select one of the options in this menu scroll to the desired item and press the ENTER key 6 1 View When you select View from the Data menu you will...

Page 22: ...e following steps should apply to most terminal software programs Downloading using Windows Hyperterminal Follow steps 1 through 9 for instructions on downloading with Win dows Hyperterminal which com...

Page 23: ...incoming line ends and the Wrap lines that exceed terminal width and then click OK 6 To set up the terminal program to capture the data click on the Transfer menu and select Capture Text Select the di...

Page 24: ...41 80 58 00 98 70 159 10 325 30 477 90 669 10 750 30 0 00 1759 SUM 321969941 1 50 322 50 1 000 0 00 1 00 0 02 50 1757 47 117 SAMPLE3 6 3 Description of Outputs RID 1757 The Record ID is a unique iden...

Page 25: ...ecords associated with the summary record MeanBlw 322 50 The average of all the below canopy PAR read ings for the raw records associated with the summary record Tau 1 000 Tau is the ratio of below ca...

Page 26: ...de location in degrees Annotation SAMPLE3 The annotation is a string used to iden tify a record in a user readable format 6 4 Erase To erase all data select Erase from the Data menu and press the ENTE...

Page 27: ...priate COM port from the drop down menu on the main screen 4 Turn on your LP 80 by pressing the power button 5 Click the Download button in the lower left of the screen or click File Download Data 6 T...

Page 28: ...ser may use to identify the reading 4 Average Above PAR The average of all the above canopy PAR readings for the raw records associated with the summary record 5 Average Below PAR The average of all t...

Page 29: ...e RID of the summary record is also associated with the summary record 7 2 Erasing Data You can use the LP 80 Utility to erase the data stored on your LP 80 Caution Once data has been erased it cannot...

Page 30: ...ease see Troubleshooting By default the LP 80 Utility automatically sets the date and time on your LP 80 each time you connect You can turn the feature off by using the Application tab under The Prefe...

Page 31: ...sts of three tabs the Data File Communications and Application tabs Figure 5 shows each tab 7 5 1 Data File Tab Figure 5 Preferences Menu Downloaded files contain column headers see Data File Formats...

Page 32: ...o automatically re send com mands to the LP 80 up to ten times Maximum Baud Rate Baud rate is the number of bits per sec ond transferred between a device and your computer By default the LP 80 is set...

Page 33: ...and Firmware Updates Use Decagon s version check web engine for updates to the LP 80 Utility or firmware Your computer must be connected to the Inter net for this feature to work To check for a newer...

Page 34: ...you configure and set most of the param eters that affect the functionality of your AccuPAR When you scroll to this menu the Config screen appears with numerous options Scrolling further down And furt...

Page 35: ...however you can also calibrate the AccuPAR on a flat board or platform that you can prop up at an angle to get more direct light from the sun The PAR level must be above 600 mols m 1 s 1 Values below...

Page 36: ...date but the longitude and latitude of the site When you select the Location menu item you will see the currently configured location Highlight the item you would like to change and press Enter In th...

Page 37: ...vings time the time will automatically adjust Leaf Distribution Use the menu is used to set the leaf distribution parameter for the plant canopy you plan to measure See the next chapter for further ex...

Page 38: ...such applications you can turn off sections of the probe starting from the base and continuing down the probe to the end When you select this menu the following screen will appear This screen shows th...

Page 39: ...he Power Noise Filter to match the frequency of the power where you live In North America and most of Asia this is 60 Hz the default value In most of Europe the electrical frequency is 50 Hz Contrast...

Page 40: ...8 CONFIG MENU AccuPAR LP 80 The About menu provides you with the serial number firmware ver sion number and copyright info 36...

Page 41: ...teith 1977 observed that dry matter production of a plant canopy is directly related to the amount of photosynthetically use ful radiation intercepted by the canopy Dry matter production is modeled as...

Page 42: ...and because most of the PAR is absorbed by a closed canopy The error becomes much more significant when measurements of total solar radiation are used because of large scattering coefficients of leave...

Page 43: ...S Measure T by placing the AccuPAR below the plant canopy Care fully place it below all of the leaves and try to keep the instrument level Press the down arrow key to make below canopy measure ments T...

Page 44: ...rs from equation 8 using U and T A value in the range of 0 1 to 0 2 should be obtained but it is possible that the light level below the canopy will be so low that U will not be accurately measured I...

Page 45: ...1 182 0 733 12 where is the zenith angle of the sun and is a leaf angle distri bution parameter see Chapter 3 for definition When x 1 the angle distribution is spherical and K simplifies to K 1 2cos...

Page 46: ...by the canopy was therefore 80 1614 0 05 The solar zenith angle was 30 and the beam frac tion was 0 881 The A value for equation 15 is again 0 86 for the canopy is unknown but unless leaves have obvio...

Page 47: ...A number of expressions have been proposed for K The most useful is from Campbell 1986 where the angle distribution of canopy elements is assumed to be ellipsoidal One can picture the angle distribut...

Page 48: ...ger at small zenith angles Equation 16 can be used in various ways to determine the leaf area index and also the leaf angle distribution for a canopy The simplest application is that of Bonhomme et al...

Page 49: ...ld like to find values for and L which minimize F X ln i KiL 2 20 subject to the constraint 0 where i are transmission coefficients measured at several zenith angles i and the Ki are the extinction co...

Page 50: ...canopy cover Take 35 0 21 The value is 0 9 p 0 92 0 92 tan35 2 1 2 0 0 210 79 0 29 Cover 0 1 0 29 0 71 Intercepted radiation averaged over an entire day can be estimated from f 1 d 25 where d is the t...

Page 51: ...7x0 9 0 87 K 0 92 tan35 2 1 2 0 9 1 774 0 9 1 182 0 733 1 14 1 94 0 59 q 0 80 2 64 0 13 0 59 1 2 d 0 211 2 0 15 f 1 d 1 0 15 0 85 9 6 LAI measurements Non Random Distribution There has been much discu...

Page 52: ...dispersed canopy L would be equal to Le figure 2 In an under dispersed canopy clumped L would be greater than Le see figure 3 leaves preferentially shade the leaves In an over dispersed canopy L woul...

Page 53: ...Figure 7 Randomly Dispersed L Le Figure 8 Under Dispersed L Le Figure 9 Over Dispersed L Le 9 7 Zenith Angle and Equation of Time The formulas for calculating elevation angle are relatively straight f...

Page 54: ...minutes or 1 15 hour for each degree east of the standard meridian and 1 15 hour for each degree west of the standard merid ian Standard meridians are at 0 15 30 etc Generally time zones run approxima...

Page 55: ...4 cos 0 2618 9 75 11 87 0 61 radians or 34 9 35 Table 4 Solar Declination and Equation of Time Date Day of Year D in Radians ET Hour Jan 1 1 0 403 0 057 Jan 10 10 0 386 0 123 Jan 20 20 0 355 0 182 Jan...

Page 56: ...330 0 363 0 213 Dec 6 340 0 391 0 151 Dec 16 350 0 406 0 075 Dec 26 360 0 408 0 007 Automatic Calculation of Zenith Angle The AccuPAR automatically determines zenith angle using the above equation and...

Page 57: ...point sensor to obtain above canopy measurements such as in timber or tropical crops you have two choices 1 Use a separate data logger with an attached PAR sensor such as a point quantum sensor or co...

Page 58: ...menu see chapter 7 To see the individual PAR readings for each of the eight probe segments download the stored data to the computer See Download section in Chapter 6 10 4 LAI Sampling in Row Crops On...

Page 59: ...g a good representative sample of the entire area below and between rows Figure 11 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...

Page 60: ...them properly placing them the wrong way in the battery holder can damage the AccuPAR The battery holders indicate which direction they should be placed After replacing the batteries press the reset...

Page 61: ...If you use it heavily each year we suggest once a year For periodic measurements one recalibration every two to three years should be adequate Before sending the instrument in contact Decagon via pho...

Page 62: ...stributors please contact them for local service and support Table 5 Troubleshooting Quick Guide If this problem occurs Refer to Instrument does not turn on Problem 1 Display is difficult to see Probl...

Page 63: ...s You may be able to fix the contrast manually which can be done using a terminal port program Contact Decagon for information regarding this procedure 3 PROBLEM Message on screen displays the followi...

Page 64: ...or longitude and positive is North and negative South for latitude Zenith angle should now be 0 to 90 degrees as expected for daylight hours and LAI and Fb should now be calculated correctly 5 PROBLEM...

Page 65: ...n menu and verify that the date and time are set properly 7 PROBLEM Message on screen displays the following SOLUTION This screen will only be displayed when you try to erase the data memory when the...

Page 66: ...and that an update is needed The firmware for the 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 ver...

Page 67: ...tion settings are locked to prevent inconsistent data from being saved To change settings navigate to the PAR or Log menu and escape out of the active reading Once the new settings are changed you can...

Page 68: ...is full You may continue 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...

Page 69: ...tings for that city If you press ESC your custom location settings will be preserved 15 PROBLEM The LP80 Utility tells me the communication port I want to use is not available for selection SOLUTION D...

Page 70: ...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 Cho...

Page 71: ...n customer support representative to obtain an RMA Shipping Directions The following steps will help to ensure the safe shipping and pro cessing of your AccuPAR LP 80 1 Ship your LP 80 in its original...

Page 72: ...evices Inc ATTN RMA insert your RMA 2365 NE Hopkins Court Pullman WA 99163 13 1 Repair Costs Manufacturer defects and instruments within the three year warranty will be repaired at no charge Non warra...

Page 73: ...977 An Introduction to Environmental Physics Springer Verlag New York Inc New York pp 159 Campbell G S 1986 Extinction coefficients for radiation in plant canopies calculated using an ellipsoidal incl...

Page 74: ...ulture Publication Documentation Wageningen The Netherlands Goudriaan J 1988 The bare bones of leaf angle distribution in radiation models for canopy photosynthesis and energy exchange Agricultural an...

Page 75: ...average leaf angle from trans mission of direct sunlight Aust J Bot 34 349 355 Lang A R G 1987 Simplified estimate of leaf area index from transmittance of the sun s beam Agric For Meteorol 41 179 18...

Page 76: ...37 Martens Scott N S L Ustin and R A Rousseau 1993 Estima tion of tree canopy leaf area index by gap fraction analysis Forest Ecology and Management 61 91 108 Norman J M 1979 Modeling the complete cro...

Page 77: ...n Welles Jon M and Shabtai Cohen Canopy Structure measurement by gap fraction analysis using commercial instrumentation Journal of Experimental Botany 47 302 1335 1342 White J D Running S W Nemani R K...

Page 78: ...9163 USA Type of Equipment AccuPAR Linear PAR LAI Cep tometer Model Number LP 80 Year of First Manufacture 2003 This is to certify that the AccuPAR model LP 80 manufactured by Decagon Devices Inc a co...

Page 79: ...ight 2000 Warranty 1 year parts and labor 16 2 Spectral Response An ideal quantum sensor would give equal emphasis to all photons between 400 and 700 nm and would exclude photons above and be low thes...

Page 80: ...80 The output of all radiation sensors tends to drift over time as the detector ages The long term shift of the sensor is less than 3 per year We recommend returning the sensor for recalibration at le...

Page 81: ...33 Setting with LP 80 Utility 26 Declaration of Conformity 74 Downloading Data 18 with LP 80 Utility 23 Dry Matter Production 37 Email 1 67 Erase Data 22 Error in Readings 38 Measurement 38 40 Externa...

Page 82: ...nstructions 68 Row Crops 47 Sample Size 53 Segment Mode Icon 34 Seller s Liability 2 Set Active Segments 34 Set Download Options Menu 31 Set Location 32 Specifications 3 Spherical Distribution 41 Tau...