Cod. +030220151 - Rel. 2.1 - 04/09/98
48
TEMPERATURE/RESISTANCE RATIOS FOR NTC
THERMISTORS
As indicated in the description of parameter /0, temperature sensors using the NTC thermistors normally
fitted in Infrared control systems change an electrical parameter, i.e. their resistance, as the temperature
varies. Below are listed the resistance values corresponding to the various temperatures. In the case of any
malfunction or any inaccurate control, users are advised to check the operation of the sensors in the
following manner:
•
with a standard thermometer determine the temperature sensed by the sensor
•
with an ohmmeter measure the resistance at the head of the sensor and compare it with the values in
the table.
In view of the variation shown by thermistors, three resistance values are given in the table for each
temperature.:
•
Rstd = the typical resistance value at the temperature indicated;
•
Rmin is the minimum value;
•
Rmax is the maximum value.
For the sake of simplicity, the values relative to only a limited number of temperatures are given.
Intermediate values can be adequately determined by interpolation.
Temperature/Resistance ratios for the Carel NTC temperature sensor
Temperature
Rmin
Rstd
Rmax
-40 ºC
181.10 k
Ω
188.40 k
Ω
195.90 k
Ω
-30 ºC
107.50 k
Ω
111.30 k
Ω
115.10 k
Ω
-20 ºC
65.80 k
Ω
67.74 k
Ω
69.74 k
Ω
-10 ºC
41.43 k
Ω
42.25 k
Ω
43.50 k
Ω
0 ºC
26.74 k
Ω
27.28 k
Ω
27.83 k
Ω
10 ºC
17.67 k
Ω
17.95 k
Ω
18.24 k
Ω
20ºC
11.95 k
Ω
12.09 k
Ω
12.23 k
Ω
30 ºC
8.21 k
Ω
8.31 k
Ω
8.41 k
Ω
40 ºC
5.73 k
Ω
5.82 k
Ω
5.92 k
Ω
50 ºC
4.08 k
Ω
4.16 k
Ω
4.24 k
Ω
60 ºC
2.95 k
Ω
3.02 k
Ω
3.09 k
Ω
70 ºC
2.17 k
Ω
2.22 k
Ω
2.28 k
Ω
80 ºC
1.62 k
Ω
1.66 k
Ω
1.71 k
Ω
90 ºC
1.22 k
Ω
1.26 k
Ω
1.30 k
Ω
