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Содержание NR-Lite

Страница 1: ...NR LITE NET RADIOMETER INSTRUCTION MANUAL REVISION 11 03 COPYRIGHT c 1998 2003 CAMPBELL SCIENTIFIC INC ...

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Страница 3: ...bility or fitness for a particular purpose CAMPBELL SCIENTIFIC INC is not liable for special indirect incidental or consequential damages Products may not be returned without prior authorization To obtain a Returned Materials Authorization RMA contact CAMPBELL SCIENTIFIC INC phone 435 753 2342 After an applications engineer determines the nature of the problem an RMA number will be issued Please w...

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Страница 5: ...R10 10X Program with Wind Speed Correction 10 6 Maintenance 12 7 Troubleshooting 12 7 1 Checking Sensor Operation 12 7 2 Radiometer produces no apparent output 13 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 Ne...

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Страница 7: ... upwards facing sensor measures the solar energy and far infra red 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 This output represents the net radiation which can be interpreted as meaning the ...

Страница 8: ...oportional to the net radiation The thermopile determines the electrical characteristics of the instrument Both upper and lower facing sensors have a field of view of 180 degrees and their angular characteristics conform closely to the so called cosine response see following sections The electrical sensitivity for the thermopile changes with temperature and no nominal sensitivity value is availabl...

Страница 9: ...ux is based on two assumptions 1 The sensor surface is spectrally black i e that it absorbs all radiation from all wavelengths see section above 2 That it has a true field of view of 180 These two properties taken together with which the net radiometer needs to comply are generally known as the cosine response A perfect cosine response will show maximum sensitivity at an angle of incidence of zero...

Страница 10: ...t of the radiation level Net radiation readings can be corrected for wind speed sensitivity using the following equation which was developed by Jerry Brotzge at the Oklahoma Climate Survey Wind Sensitivity equation for the NR LITE Rn cor Rn obs U 5 m s Rn cor Rn obs 1 0 A U 5 0 U 5 m s Where Rn cor Net radiation corrected for wind speed Rn obs Net radiation not corrected for wind speed U Horizonta...

Страница 11: ...itivity 2 Sensor Specifications Spectral Spectral range 0 2 to 100 µm Detector type Thermopile Detector protection Teflon coating Detector profile Conical Directional Directional error 0 60 at 1000 W m 2 30 W m 2 Sensor asymmetry 5 typical 10 worst case ...

Страница 12: ...ed 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 Mount the sensor as follows 1 Attach PN 14264 mounting bracket to the vertical mounting pipe or UT018 crossarm using the hardware provided The hole through PN 14264 has two different diamet...

Страница 13: ...NR LITE Net Radiometer 7 FIGURE 6 NR LITE Mounting Options 14264 Mounting Bracket NR LITE UT018 Crossarm 14264 Mounting Bracket NR LITE ...

Страница 14: ...23X 21X CR7 Radiation Signal White Differential H Differential H Differential H Signal Reference Green Differential L Differential L Differential L Jumper to AG Shield Clear G TABLE 2 Datalogger Connections for Single Ended Measurement Function Color CR10X CR510 CR23X 21X CR7 Radiation Signal White S E Channel S E Channel S E Channel Signal Reference Green AG Shield Clear G White Radiation Signal ...

Страница 15: ...e manufacturer which shows the sensor serial number and a sensitivity or calibration factor This calibration factor after conversion is used in the datalogger program Always cross check to ensure that the serial number of your NR LITE and the number on the calibration certificate are identical The serial number and sensitivity are also shown on a small label attached to the connecting arm near the...

Страница 16: ...f time is P92 1 0 Minutes Seconds into a 2 60 Interval same units as above 3 10 Set Output Flag High Flag 0 3 Real Time P77 1 110 Day Hour Minute midnight 0000 4 Average P71 1 1 Reps 2 1 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 fact...

Страница 17: ...el 4 2 Loc Rn_obs 5 63 29 Mult Multiplier for specific sensor 6 0 Offset in units of W m 2 mV see above apply wind speed correction factor Rn cor Rn obs 1 0 0 021286 U 5 0 when U 5 m s 3 If X F P89 1 1 X Loc Wspd_m_s 2 3 3 5 F 4 30 Then Do 4 Z X F P34 1 1 X Loc Wspd_m_s 2 5 F 3 24 Z Loc scratch_1 5 Z X F P37 1 24 X Loc scratch_1 2 021286 F 3 25 Z Loc scratch_2 6 Z X F P34 1 25 X Loc scratch_2 2 1 ...

Страница 18: ...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 LITE should be recalibrated every two years Contact CSI for an RMA number before returning the sensor for recalibration 7 Troubleshooting 7 1 Checking Sensor Operation To effectively check the instrument s operation you wil...

Страница 19: ...t stabilize Put your hand over the upper sensor Assuming that your hand is at a higher temperature than the sensor the positive reading should increase Conversely if the sensor is warmer than your hand the reading will decrease 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...

Страница 20: ... may be greater For indoor climate studies smaller values are to be expected unless solar radiation is present A typical value for a room when facing a wall and a relatively cold window is 50 W m 2 Are you using the correct calibration factor Note that this factor is unique for each individual sensor as noted on the calibration certificate provided with that sensor Did you convert the factor to th...

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