background image

 
 
 
 

 
 

11 

 

Temperature 

[EC] 

 

Resistance 

[

Ω

 

Temperature 

[EC] 

 

Resistance 

[

Ω

 

Temperature 

[EC] 

 

Resistance 

[

Ω

 

-30 
-29 
-28 
-27 
-26 
-25 
-24 
-23 
-22 
-21 
-20 
-19 
-18 
-17 
-16 
-15 
-14 
-13 
-12 
-11 
-10 

-9 
-8 
-7 
-6 
-5 
-4 
-3 
-2 
-1 

 

135200 
127900 
121100 
114600 
108600 
102900 

97490 
92430 
87660 
83160 
78910 
74910 
71130 
67570 
64200 
61020 
58010 
55170 
52480 
49940 
47540 
45270 
43110 
41070 
39140 
37310 
35570 
33930 
32370 
30890 

 










10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 

 

29490 
28150 
26890 
25690 
24550 
23460 
22430 
21450 
20520 
19630 
18790 
17980 
17220 
16490 
15790 
15130 
14500 
13900 
13330 
12790 
12260 
11770 
11290 
10840 
10410 
10000 

9605 
9227 
8867 
8523 

 

30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 
48 
49 
50 
51 
52 
53 
54 
55 
56 
57 
58 
59 

 

8194 
7880 
7579 
7291 
7016 
6752 
6500 
6258 
6026 
5805 
5592 
5389 
5193 
5006 
4827 
4655 
4489 
4331 
4179 
4033 
3893 
3758 
3629 
3504 
3385 
3270 
3160 
3054 
2952 
2854 

 

Table 1.2  

Resistance values versus temperature in °C of the CNR 4's thermistor.   

 
 

Relatively  small  errors  occur  when  the  CNR  4  is  not  in  thermal  equilibrium.  This  happens  for  example  when  the 
heater  is  on,  or  when  the  sun  is  shining.  When  the  heater  and  ventilator  are  on,  the  largest  expected  deviation 
between real sensor temperature and Pt-100 or thermistor reading is less than 0.5 degree.  
The  internal  temperature  sensors  will  not  give  a  good  indication  of  ambient  air  temperature;  at  1000  Watts  per 
square  meter  Solar  Radiation,  and  no  wind,  the  instrument  temperature  can  rise  a  few  degrees  above  ambient 
temperature. This will not affect the readings of the CNR 4 
The  offsets  of  both  pyranometers  and  pyrgeometers  might  be  larger  than  5  Watts  per  square  meter  if  large 
temperature gradients are forced on the instrument (larger than 5 K/hr). This happens for example when rain hits 
the instrument. The occurrence of this can be detected using the temperature sensor readout. It can be used as a 
tool for quality assurance of your data. 

Summary of Contents for CNR 4

Page 1: ...Net Radiometer CNR 4 Instruction Manual...

Page 2: ...LITY Kipp Zonen guarantees that the product delivered has been thoroughly tested to ensure that it meets its published specifications The warranty included in the conditions of delivery is valid only...

Page 3: ...nder our sole responsibility that the product Type CNR 4 Name Net Radiometer To which this declaration relates is in conformity with the following standards Imissions EN 50082 1 Group standard Emissio...

Page 4: ...f the pyranometer 18 2 2 2 Spectral properties of the pyranometer 20 2 2 3 Directional Cosine response of the pyranometer 20 2 3 Properties of the pyrgeometer 22 2 3 1 Window heating offset 22 2 3 2 W...

Page 5: ...ient air flow over the domes and windows to minimize the formation of dew and reduce the frequency of cleaning The integrated heater can be used to melt frost The CNR 4 specifications when used with C...

Page 6: ...as also 8 pins but only 6 wires are coming out of the cable Exchanging the connectors will not damage the CNR 4 To prevent mix up of the cables after installation it is advised to mark the cables with...

Page 7: ...rgeometer Upper Oben Sup rieur Superior Pyrgeometer Lower Unten Inf rieur M s bajo Blue Blau Bleu Azul Connect with Anschluss an Relier Conectar con Yellow Gelb Jaune Amarillo Green Gr n Vert Verde Ho...

Page 8: ...d covered with a black sleeve If the CNR 4 rod is grounded to the mast it is advised not to connect the shielding on the data logger side This might cause ground loops and offsets in the signal Figure...

Page 9: ...ween the pyrgeometer and the object that it is facing This implies that the pyrgeometer will generate a positive voltage output V when it faces an object that is hotter than its own sensor housing and...

Page 10: ...in a positive signal To measure the Far Infrared irradiances with the two pyrgeometers separately the Pt 100 output is required The formula 1 2 is used to calculate the Far Infrared irradiance of the...

Page 11: ...39 100 78 101 17 101 56 101 95 102 34 102 73 103 12 103 51 103 90 104 29 104 68 105 07 105 46 105 85 106 24 106 63 107 02 107 40 107 79 108 18 108 57 108 96 109 35 109 73 110 12 110 51 110 90 111 28...

Page 12: ...2952 2854 Table 1 2 Resistance values versus temperature in C of the CNR 4 s thermistor Relatively small errors occur when the CNR 4 is not in thermal equilibrium This happens for example when the hea...

Page 13: ...pyranometer E lower pyranometer 1 4 In this formula E is calculated according to formula 1 1 Net Solar radiation will always be positive Checking this can be used as a tool for quality assurance of y...

Page 14: ...ature column nine tracks the ambient temperature Under cloudy conditions this is logical cloud bases will be colder than the ambient temperature at instrument level the temperature difference depends...

Page 15: ...e upper pyrgeometer Figure 1 2 3 clear day for the downward facing pyrgeometer Upper pyrgeometer day with alterna3ng cloud elds pyrgeometer U_emf Sensi3vity W m Temp YSI 44031 C Upwelling signal downw...

Page 16: ...cooling The sky and the ground temperature can be calculated from the measured values of the sensors using formulas 1 6 and 1 7 day night Cloudy clear 20 C 20 C pyrgeo Up pyrgeo low pyrano up pyrano...

Page 17: ...g improve the accuracy significantly Due to the fact that the Net Solar radiation can be very intense 1000 Watts per square metre compared to a typical 100 for the Net Far Infrared radiation the accur...

Page 18: ...ature C 40 to 80 CE according to EC guideline 89 336 EEC 73 23 EEC Environmental protection IP 67 2 2 Properties of the pyranometer The pyranometer consists of a thermopile sensor and a glass dome bot...

Page 19: ...sensitivity N S 40 C to 10 C 4 10 C to 40 C N S 40 C to 80 C Definition Maximum error due to any change of instrument temperature within the indicated temperature interval Tilt error 1 Definition Max...

Page 20: ...nition Deviation of the product of spectral absorption and spectral transmittance from the corresponding mean within the indicated spectral range Uncertainty in daily total 5 95 confidence level Defin...

Page 21: ...t absorbs all radiation from all wavelengths Its field of view is 180 degrees The directional properties are similar to that of a blackbody Another way of expressing these directional properties is to...

Page 22: ...sponse or cosine response of the pyranometer On the horizontal axis the zenith angle is shown 0E zenith angle equals 90E angle of incidence The vertical axis shows the deviation from the ideal cosine...

Page 23: ...range This error is neglected however in the net radiation calculation this is justified because the solar radiation is always dominant when this error occurs Due to its construction the window heatin...

Page 24: ...indow heating offset W m 6 0 to 1000 W m solar irradiance Definition Caused by heating of the dome due to solar radiation Field of view Upper detector Lower detector 180 150 Definition Sensor opening...

Page 25: ...ectivity of the total instrument 2 3 5 Directional Cosine response of the pyrgeometer The measurement of the Far Infrared radiation falling on a surface also called irradiance or radiative flux requir...

Page 26: ...e significant Dew deposition will probably take place under conditions with large Far Infrared irradiation from the pyrgeometer detector to the clear sky typically minus 100 Watts per metre square Und...

Page 27: ...A table stating the resistance values can be found in table 1 1 The thermistor has a much larger resistance value than the Pt 100 also the change in resistance with respect to temperature in absolute...

Page 28: ...librated against the World Reference at WMO in Davos 3 3 Recalibration of pyranometers and pyrgeometers We suggest recalibration for all sensors pyranometers and pyrgeometers to be performed every two...

Page 29: ...nt by less than 1 The Net Radiometer should be installed horizontally using the level on the body of the CNR 4 For installation in buildings or in solar energy applications you will often have to moun...

Page 30: ...or cover black part in picture below can be removed by just pulling it down from the CNR 4 The filter needs to be checked for dust and particles every 6 12 months It can be cleaned by simply washing i...

Page 31: ...e starting the second test measurement let the pyranometer rest for at least five minutes to let it regain its thermal equilibrium For testing set a voltmeter to its most sensitive range setting Darke...

Page 32: ...ermistor Using a meter which measures resistance you can check the operation of the thermistor If connected properly the resistance of two wires of the thermistor should be measured The value can be r...

Page 33: ...bject The top U bolts allow rotation of the CNR 4 rod while the extra screw under the front U bolt allows the rod to tilt All mounting material for fixation to a horizontal or vertical pole is include...

Page 34: ...33 Fig 7 2 CMB 1 mounting examples with CNR 4 albedometer and pyranometer...

Page 35: ...clude the following items A delivery includes One CNR 4 One mounting rod Two cables Two drying cartridges Four calibration values on 2 calibration sheets long and short wave One CD with instruction ma...

Page 36: ...Here recalibration to the highest standards can be performed at low cost Recalibration can usually be performed within four weeks If required urgent recalibration can be accomplished in three weeks or...

Page 37: ...ro de repuestos Passion for Precision Go to www kippzonen com for your local distributor or contact your local sales office HEAD OFFICE Kipp Zonen B V Delftechpark 36 2628 XH Delft P O Box 507 2600 AM...

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