NR-LITE2 Net Radiometer Revision: 3/13 C o p y r i g h t © 1 9 9 8 - 2 0 1 3 C a m p b e l l S c i e n t i f i c , I n c .
Warranty “PRODUCTS MANUFACTURED BY CAMPBELL SCIENTIFIC, INC. are warranted by Campbell Scientific, Inc. (“Campbell”) to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless otherwise specified in the corresponding Campbell pricelist or product manual. Products not manufactured, but that are re-sold by Campbell, are warranted only to the limits extended by the original manufacturer.
Assistance Products may not be returned without prior authorization. The following contact information is for US and international customers residing in countries served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs for customers within their territories. Please visit www.campbellsci.com to determine which Campbell Scientific company serves your country. To obtain a Returned Materials Authorization (RMA), contact CAMPBELL SCIENTIFIC, INC., phone (435) 227-9000.
Table of Contents PDF viewers: These page numbers refer to the printed version of this document. Use the PDF reader bookmarks tab for links to specific sections. 1. Introduction .................................................................1 2. Cautionary Statements...............................................1 3. Initial Inspection .........................................................1 3.1 Ships With............................................................................................2 4.
Table of Contents 9. Troubleshooting........................................................20 9.1 9.2 9.3 Checking Sensor Operation ............................................................... 20 Radiometer Produces No Apparent Output ....................................... 21 Readings Are Not As Expected ......................................................... 21 4-1. 4-2. 5-1. 5-2. 5-3. 6-1. 7-1. Siting and mounting diagram for the NR-LITE2.................................
NR-LITE2 Net Radiometer 1. Introduction The NR-LITE2 is a high-output thermopile sensor which measures the algebraic sum of incoming and outgoing all-wave radiation (both short-wave and long-wave components). Incoming radiation consists of direct (beam) and diffuse solar radiation plus long-wave irradiance from the sky. Outgoing radiation consists of reflected solar radiation plus the terrestrial long-wave component. The NR-LITE2 is equipped with PTFE-coated (polytetrafluoroethylene) sensor surfaces.
NR-LITE2 Net Radiometer 3.1 Ships With (1) WRR traceable calibration certificate (1) Mounting arm from original manufacturer (1) Bird stick from original manufacturer (1) ResourceDVD 4. Quickstart Please review Section 7, Operation, for wiring, CRBasic programming, and Edlog programming. 4.1 Siting Considerations 1. Mount the sensor so that no shadow will be cast on it at any time of day from obstructions such as trees, buildings, the mast, or structure on which it is mounted (1 in FIGURE 4-1). 2.
NR-LITE2 Net Radiometer 4.2 Mounting The mounting bracket kit, pn 26120, is used to mount the NR-LITE2 directly to a vertical pipe, or to a CM202, CM204, or CM206 crossarm. Mount the sensor as follows: CAUTION 1. Screw in the bird repellent stick, which is shipped with the calibration documentation (4 in FIGURE 4-1). 2. Attach the 26120 mounting bracket to the vertical mounting pipe, or CM200-series crossarm using the provided U-bolt (FIGURE 4-2). 3.
NR-LITE2 Net Radiometer Support Arm 26120 Pole 26120 Support Arm Crossarm FIGURE 4-2. Mounting the NR-LITE2 onto a pole (top) and crossarm (bottom) via the 26120 Mounting Kit 4.3 Use SCWin to Program Datalogger and Generate Wiring Diagram The simplest method for programming the datalogger to measure the NRLITE2 is to use Campbell Scientific’s SCWin Program Generator.
NR-LITE2 Net Radiometer NOTE The SCWin example provided here is for no wind speed correction. SCWin also supports dynamic wind speed correction; refer to the SCWin help for more information. 1. Open Short Cut and click on New Program. 2. Select the datalogger and enter the scan interval.
NR-LITE2 Net Radiometer 6 3. Select NR-LITE2 Net Radiometer (no wind speed correction), and select the right arrow (in center of screen) to add it to the list of sensors to be measured, and then select Next. 4. Define the name of the public variable and enter the calibration factor. The public variable defaults to NR_Wm2. The calibration factor is unique to each sensor. This value is provided on the certification of calibration that is shipped with your sensor.
NR-LITE2 Net Radiometer 5. Choose the outputs and then select Finish. 6. In the Save As window, enter an appropriate file name and select Save. 7. In the Confirm window, click Yes to download the program to the datalogger. 8. Click on Wiring Diagram and wire according to the wiring diagram.
NR-LITE2 Net Radiometer 5. Overview The NR-LITE2 is used for measuring solar and far infrared radiation balance. This balance is known as the net (total) radiation. Its upwards facing sensor measures the solar energy and far infrared energy that is received from the entire hemisphere (180° field of view). Its downwards facing sensor measures the energy received from the surface of the soil. The two readings are automatically subtracted and the result converted to a single output signal.
NR-LITE2 Net Radiometer FIGURE 5-1. Electrical circuit for the NR-LITE2 Net Radiometer 5.2 Spectral Properties The upwards facing sensor is calibrated for solar radiation wavelengths. The following assumptions are made: 5.3 • The downwards facing sensor has the same sensitivity. However, since the two sensors may not be perfectly symmetrical, this assumption may not always be true, but differences are small. • The NR-LITE2’s sensitivity is the same for both solar and infrared radiation.
Error NR-LITE2 Net Radiometer Angle of Incidence FIGURE 5-2. Cosine response of a typical net radiometer 5.4 Sensitivity to Wind Speed The calibration of the NR-LITE2 is carried out at zero wind speed. At any other wind speed, the sensitivity will decrease. It has been shown that this decrease in sensitivity is less than 1% of reading per meter per second wind speed, and the effect is essentially independent of the radiation level.
NR-LITE2 Net Radiometer Differences between the NR-Lite and CNR1 as a function of wind speed for daytime conditions during 7 May ─ 6 June, 1998. (a) No correction. (b) Eq. (4) applied as a correction. FIGURE 5-3. NR-LITE2 wind sensitivity 6.
NR-LITE2 Net Radiometer 6.1 6.2 Spectral Spectral range: 0.2 to 100 μm Detector type: Thermopile Detector protection: PTFE coating Detector profile: Conical Directional Directional error (0° to 60°C at 1000 W m-2): <30 W m-2 Sensor asymmetry: 6.3 ±5% typical, (±10% worst case) Mechanical Housing material: Anodized aluminum Cable material: Polyurethane Weight: 200 g Cable length: 15 m (can be extended up to 100 m) Physical dimensions (FIGURE 6-1) Sensor: 8.0 cm (3.
NR-LITE2 Net Radiometer 7. Operation 7.1 Wiring The NR-LITE2 can be measured with a differential or single-ended channel on the datalogger; a differential channel is recommended. FIGURE 7-1 provides the NR-LITE2 wiring. Datalogger connections are shown in TABLE 7-1 for differential measurements and TABLE 7-2 for single-ended measurements. Red Radiation Signal Blue Signal Reference Black Shield (User supplied jumper wire for differential measurement only) FIGURE 7-1.
NR-LITE2 Net Radiometer TABLE 7-2. Datalogger Connections for Single-Ended Measurement 7.2 Function Color CR10X, CR510, CR500 Radiation Signal Red S.E. Channel Signal Reference Blue AG Shield Black G CR23X, 21X, CR7 CR800, CR850, CR1000, CR3000, CR5000, CR9000(X) S.E. Channel S.E. Channel Datalogger Programming NOTE This section is for users who write their own datalogger programs.
NR-LITE2 Net Radiometer the calibration factor into 1000. For example, if the calibration factor is 15.8 µV/(W m-2), the multiplier is: 1000/15.8 = 63.29 (W m-2)/mV 7.2.3 Example Programs 7.2.3.1 CR3000 Example Program without Wind Speed Correction Shown below is an example program written for the CR3000 datalogger. TABLE 7-3 provides the wiring for the example program. In this example, the datalogger measures the output from the sensor every 5 seconds and outputs the average net radiation every hour.
NR-LITE2 Net Radiometer 7.2.3.2 CR1000 Example Program with Wind Speed Correction Shown below is an example program written for the CR1000 datalogger. TABLE 7-4 provides the wiring for the example program. Besides measuring the NR-LITE2, the program also measures wind speed and applies the correction factor as described in Section 5.4, Sensitivity to Wind Speed. Average net radiation and wind speed are output every hour. TABLE 7-4.
NR-LITE2 Net Radiometer VoltDiff(NR_Wm2,1,mv25,2,True,0,_60Hz,100,0) If WS_ms>=5 Then CNR_Wm2=NR_Wm2*(1+0.021286*(WS_ms-5)) Else CNR_Wm2=NR_Wm2 EndIf 'Call Data Tables and Store Data CallTable(Table1) CallTable(Table2) NextScan EndProg 7.2.3.3 CR10(X) Example Program without Wind Speed Correction Shown below is an example program written for the CR10(X) datalogger. TABLE 7-5 provides the wiring for the example program.
NR-LITE2 Net Radiometer 7.2.3.4 CR10X Example Program with Wind Speed Correction This example measures the NR-LITE2 using a single-ended input and instruction Volt (SE) (P1). The program also measures wind speed and applies the correction factor as described in Section 5.4, Sensitivity to Wind Speed. Average net radiation and wind speed are output every hour. TABLE 7-6 provides the wiring for this example program. TABLE 7-6.
NR-LITE2 Net Radiometer 4: Z=X+F (P34) 1: 1 2: -5 3: 24 X Loc [ Wspd_m_s ] F Z Loc [ scratch_1 ] 5: Z=X*F (P37) 1: 24 2: .
NR-LITE2 Net Radiometer 8. Maintenance The radiometer is an ‘all weather’ instrument and is very stable, but should be handled with care. It requires little periodic maintenance, apart from cleaning the sensor surfaces carefully with a soft cloth using water or alcohol. The NR-LITE2 should be recalibrated every two years. An RMA number is required before returning the sensor for recalibration; refer to the Assistance section in the beginning of this manual for more information. 9. Troubleshooting 9.
NR-LITE2 Net Radiometer Conversely, if the sensor is warmer than your hand, the reading will decrease. 8. Check the radiometer’s sensitivity to thermal shocks by touching the edge of the sensor (the blank metal) with your hand for some seconds. The resultant shock will result in a signal drift, or a zero offset that will take some time to settle back to zero. 9. Adjust the range of the voltmeter so that the expected full-scale output of the radiometer is about the same as the range of the voltmeter.
NR-LITE2 Net Radiometer 22
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