Computer Program - ILX Lightwave Temperature Controller LDT-5525 User Manual

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 -1 to
signify the end of the resistance data and temperature data.
A small sample data file is included below as an example of the data format and
end of data marker (R = 1).
Temperature
-20
-10
0
10
20
25
30
40
50
-1
Run the STEIN1 program. The best curve fitting values for C1, and C2 will be
displayed. Enter these numbers into the LDT-5525 Temperature Controller.
06_07
Resistance
97072
55326
32650
19899
12492
10000
8056.8
5326.4
3602.3
-1
A
C H A P T E R
29
LDT-5525