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Summary of Contents for Campbell NR-Lite
- Page 1 NR-LITE NET RADIOMETER INSTRUCTION MANUAL REVISION: 11/03 COPYRIGHT (c) 1998-2003 CAMPBELL SCIENTIFIC, INC.
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- Page 3 CAMPBELL SCIENTIFIC, INC. CAMPBELL SCIENTIFIC, INC. will return such products by surface carrier prepaid. This warranty shall not apply to any CAMPBELL SCIENTIFIC, INC. products which have been subjected to modification, misuse, neglect, accidents of nature, or shipping damage. This warranty is in lieu of all other warranties, expressed or implied, including warranties of merchantability or fitness for a particular purpose.
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Page 5: Table Of Contents
7.3 Readings are not as expected ..............14 Figures 1. General View and Dimensions of NR-LITE ..........1 2. Electrical Circuit for the NR-LITE Net Radiometer ........2 3. Approximate Spectral Sensitivity and Solar/F.I.R. Radiation.....3 4. Cosine Response of a Typical Net Radiometer...........4 5. - Page 6 This is a blank page.
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Page 7: General Description
NR-LITE Net Radiometer The NR-LITE is a high-output thermopile sensor which measures the algebraic sum of incoming and outgoing all-wave radiation (i.e. 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. -
Page 8: Electrical Properties
FIGURE 2. Electrical Circuit for the NR-LITE Net Radiometer 1.2 Spectral Properties The spectral properties of the NR-LITE are determined by the Teflon surface of the sensors. An approximate spectral sensitivity response curve for the instrument combined with the spectrum of the sun under a clear sky, and the spectrum of outgoing far infra-red radiation (F.I.R.) is shown in Figure 3,... -
Page 9: Directional/Cosine Response
However, since the two sensors may not be perfectly symmetrical, this assumption may not always be true, but any differences are small. • It is also assumed that the NR-LITE’s sensitivity is the same for both solar and infrared radiation. 1.3 Directional/Cosine Response... -
Page 10: Sensitivity To Wind Speed
FIGURE 4. Cosine Response of a Typical Net Radiometer 1.4 Sensitivity to Wind Speed The calibration of the NR-LITE 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. -
Page 11: Sensor Specifications
NR-LITE Net Radiometer FIGURE 5. NR-LITE Wind Sensitivity 2. Sensor Specifications Spectral 0.2 to 100 µm Spectral range: Detector type: Thermopile Detector protection: Teflon coating Detector profile: Conical Directional Directional error: (0 - 60° at 1000 W m <30 W m Sensor asymmetry: ±5% typical, (±10% worst case). -
Page 12: Installing The Nr-Lite
1.5 m above the ground surface. It is recommended that the NR-LITE be mounted to a separate vertical pipe at least 25’ from any other mounting structures. PN 14264 mounting bracket is used to mount the NR- LITE directly to a vertical pipe, or to a UT108 Tower Mounting Bracket and Crossarm. - Page 13 NR-LITE Net Radiometer 14264 Mounting Bracket NR-LITE UT018 Crossarm 14264 Mounting Bracket NR-LITE FIGURE 6. NR-LITE Mounting Options...
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Page 14: Datalogger Connections For Differential Measurement
NR-LITE Net Radiometer 4. Wiring The NR-LITE can be measured with a differential or single-ended channel on the datalogger; a differential channel is recommended. White Radiation Signal Green Signal Reference (User supplied jumper wire for differential measurement only) Clear Shield FIGURE 7. -
Page 15: Datalogger Programming
NR-LITE Net Radiometer 5. Datalogger Programming The NR-LITE outputs a low-level voltage ranging from 0 to a maximum of about 15 mV. A differential voltage measurement (Instruction 2) is recommended because it has better noise rejection than a single-ended measurement. If a differential channel is not available, a single-ended measurement (Instruction 1) can be used. - Page 16 Loc [ Net_rad ] 5.3.2 Example 2, CR10X Program with Wind Speed Correction Example 2 measures the NR-LITE using a Single-Ended input and Instruction 1. The program also measures wind speed and applies the correction factor as described in Section 1.4. Average net radiation and wind speed are output every hour.
- Page 17 3: 21 Low Level AC, Output Hz 4: 1 Loc [ Wspd_m_s ] 5: .0980 Mult 6: 0 Offset ;measure NR-LITE net radiation 2: Volt (SE) (P1) 1: 1 Reps 2: 3** 25 mV Slow Range 3: 1* SE Channel...
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Page 18: Checking Sensor Operation
It requires little periodic maintenance, apart from cleaning the sensor surfaces carefully with a soft cloth using water or alcohol. The NR-LITE should be recalibrated every two years. Contact CSI for an RMA number before returning the sensor for recalibration. -
Page 19: Radiometer Produces No Apparent Output
Hold the instrument only by its mounting arm at all times. Follow the procedure outlined below: • Connect the NR-LITE wires to the voltmeter. Connect the white wire to the positive lead and the green wire to the negative lead. • Select the most sensitive range on the voltmeter. -
Page 20: Readings Are Not As Expected
Did you convert the factor to the correct value for the datalogger program? (See Section 5, above). • Check the datalogger program for errors. If you cannot resolve your problems, please contact Campbell Scientific for further advice.
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