HTM25X0LF Measurement Specialties, HTM25X0LF Datasheet - Page 5

• Manufacturer Part Number: HTM25X0LF
• Description: Temperature And Relative Humidity Module
• Manufacturer: Measurement Specialties

HTM25X0LF – Temperature and Relative Humidity Module
HTM2500LF TEMPERATURE SENSOR: DIRECT NTC OUTPUT
•
Depending on the needed temperature measurement range and associated accuracy, we suggest two methods
to access to the NTC resistance values.
as the material parameter β in reality also depend on temperature. So this approach is suitable for describing a
restricted range around the rated temperature or resistance with sufficient accuracy.
complicated approaches (e.g. the Steinhart-Hart equation) are used or the resistance/temperature relation as
given in tabulation form. The below table has been experimentally determined with utmost accuracy for
temperature increments of 1 degree.
Actual values may also be influenced by inherent self-heating properties of NTCs. Please refer to MEAS-
France/Humirel Application Note HPC106 “Low power NTC measurement”.
•
HTM25X0LF HPC169 Rev 0
The exponential relation only roughly describes the actual characteristic of an NTC thermistor can, however,
For practical applications, a more precise description of the real R/T curve may be required. Either more
Typical temperature output
Temperature look-up table
Temp (°C)
-40
-35
-30
-25
-20
-15
-10
10
15
20
-5
0
5
R
R
T, T
β
e
T
N
N
NTC resistance in Ω at temperature T in K
Temperature in K
Beta value, material specific constant of NTC
NTC resistance in Ω at rated temperature T in K
Base of natural logarithm (e=2.71828)
195652
148171
113347
87559
68237
53650
42506
33892
27219
22021
17926
14674
12081
R (Ω)
R
T
www.meas-spec.com
=
R
N
5/9
×
Temp (°C)
e
β
⎛
⎜ ⎜
⎝
25
30
35
40
45
50
55
60
65
70
75
80
85
T
1
−
T
1
N
⎞
⎟ ⎟
⎠
10000
R (Ω)
8315
6948
5834
4917
4161
3535
3014
2586
2228
1925
1669
1452
July 2009