Campbell CNR4 Manual de Instruções descarregar pdf (Página 24)

CNR4 Net Radiometer

In this equation, C is the sensitivity of the sensor.

T is in Kelvin, and not in Celsius or Fahrenheit.

The downward-facing pyrgeometer measures the far infrared radiation that is

emitted by the ground. The upward-facing pyrgeometer measures the far

infrared radiation from the sky. As the sky is typically colder than the

instrument, one can expect negative voltage signals from the upward-facing

pyrgeometer. Equation 7-2 is used to calculate the far infrared irradiance of the

sky and of the ground.

7.1.3 Measuring CNR4 Temperature with Thermistor

The CNR4 has two temperature sensors built inside: thermistor and Pt-100;

both have identical accuracy. Using the thermistor is recommended when

using Campbell Scientific dataloggers. The thermistor has a greater resistance

(10 kΩ @ 25 °C) than Pt-100 sensor (100 Ω @ 0 °C), and the change in

resistance with respect to temperature, in absolute terms, is greater. Therefore,

the cable resistance can be neglected, and the thermistor can easily be

measured using Half-Bridge Measurement instruction on Campbell Scientific

dataloggers.

TABLE 7-1 shows the thermistor resistance values as a function of

temperature.

TABLE 7-1. Resistance values versus CNR4’s thermistor temperature in °C

Temperature

[°C]

Resistance

[Ω]

Temperature

[°C]

Resistance

[Ω]

Temperature

[°C]

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

135200

127900

121100

114600

108600

102900

97490

92430

87660

83160

78910

74910

71130

67570

64200

61020

58010

55170

52480

49940

47540

45270

43110

29490

28150

26890

25690

24550

23460

22430

21450

20520

19630

18790

17980

17220

16490

15790

15130

14500

13900

13330

12790

12260

11770

11290

8194

7880

7579

7291

7016

6752

6500

6258

6026

5805

5592

5389

5193

5006

4827

4655

4489

4331

4179

4033

3893

3758

3629

NOTE

1 2 ... 19 20 21 22 23 24 25 26 27 28 29 ... 69 70

Comentários a estes Manuais

Sem comentários

Campbell CNR4 Manual de Instruções Página 24

Comentários a estes Manuais

Manuais e produtos relacionados com Medição, teste e controlo Campbell CNR4