GHM Delta OHM LPPIRG01, Operating Manual, Page: 11 / 26

LPPIRG01
- 11 -
V2.1
5 MEASUREMENT IN THE MODEL WITH ANALOG OUTPUT
Measure the NTC resistance R
NTC
(Ω) and calculate the pyrgeometer temperature T
B
(K)
by using the formula 3:
1
T
B
= a + b log(R
NTC
) + c log(R
NTC
) 3 (3)
Where:
a = 10297.2 x 10
-7
b = 2390.6 x 10 -7
c = 1.5677 x 10
-7
The temperature is expressed in Kelvin.
Table 5.1 indicates the correspondence between T
B
and R
NTC
for temperature values
between -25 °C and +58 °C. To obtain the temperature value in Kelvin, add 273.15 to
the temperature value in degrees Celsius in the table.
TAB. 5.1: correspondence between pyrgeometer temperature and NTC resistance
T
B
(°C) R
NTC
(Ω) T
B
(°C) R
NTC
(Ω) T
B
(°C) R
NTC
(Ω)
-25 103700 3 25740 31 7880
-24 98240 4 24590 32 7579
-23 93110 5 23500 33 7291
-22 88280 6 22470 34 7016
-21 83730 7 21480 35 6752
-20 79440 8 20550 36 6499
-19 75390 9 19660 37 6258
-18 71580 10 18810 38 6026
-17 67970 11 18000 39 5804
-16 64570 12 17240 40 5592
-15 61360 13 16500 41 5388
-14 58320 14 15810 42 5193
-13 55450 15 15150 43 5006
-12 52740 16 14520 44 4827
-11 50180 17 13910 45 4655
-10 47750 18 13340 46 4489
-9 45460 19 12790 47 4331
-8 43290 20 12270 48 4179
-7 41230 21 11770 49 4033
-6 39290 22 11300 50 3893
-5 37440 23 10850 51 3758
-4 35690 24 10410 52 3629
-3 34040 25 10000 53 3505
-2 32470 26 9605 54 3386
-1 30980 27 9228 55 3386
0 29560 28 8868 56 3271
1 28220 29 8524 57 3161
2 26950 30 8195 58 3055