C H A P T E R A
Computer Program
We have included a computer program called STEIN1 that uses a least squares curve fitting routine to determine the values of C1 and C2. The program is written in IBM's advanced BASICA.
You must create a data file for your thermistor that describes the resistance at various temperatures. The temperature verses resistance calibration data can be obtained from the thermistor manufacturer. Enter the resistance at various temperatures as data points into an ASCII file. You can write the data file on a word processor, but you must use non document mode so special word processing characters are not inserted into the data file. Format the data with one temperature resistance pair per line and at least one space separating the two numbers. Temperatures should be in centigrade and resistances in ohms. For an accurate determination of the coefficients, we recommend that you use at least twenty data points uniformly spread over the intended range of use. Enter a
A small sample data file is included below as an example of the data format and end of data marker (R = 1).
Temperature | Resistance |
97072 | |
55326 | |
0 | 32650 |
10 | 19899 |
20 | 12492 |
25 | 10000 |
30 | 8056.8 |
40 | 5326.4 |
50 | 3602.3 |
Run the STEIN1 program. The best curve fitting values for C1, and C2 will be displayed. Enter these numbers into the
06_07 | 29 |
