wpc60

KTY81_110.txt

-55	0.99	475	490	505	3.02
-50	0.98	500	515	530	2.92
-40	0.96	552	567	582	2.74
-30	0.93	609	624	638	2.55
-20	0.91	669	684	698	2.35
-10	0.88	733	747	761	2.14
0	0.85	802	815	828	1.91
10	0.83	874	886	898	1.67
20	0.8	950	961	972	1.41
25	0.79	990	1000	1010	1.27
30	0.78	1029	1040	1051	1.39
40	0.75	1108	1122	1136	1.64
50	0.73	1192	1209	1225	1.91
60	0.71	1278	1299	1319	2.19
70	0.69	1369	1392	1416	2.49
80	0.67	1462	1490	1518	2.8
90	0.65	1559	1591	1623	3.12
100	0.63	1659	1696	1733	3.46
110	0.61	1762	1805	1847	3.83
120	0.58	1867	1915	1963	4.33
125	0.55	1919	1970	2020	4.66
130	0.52	1970	2023	2077	5.07
140	0.45	2065	2124	2184	6.28
150	0.35	2145	2211	2277	8.55

main.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys

if __name__ == '__main__':
    # load datasheet values from file
    # format:
    # (temp, temp_coef, res_min, res, res_max, temp_error)
    data = []
    with open('KTY81_110.txt') as ds:
        lines = ds.read().splitlines()
        data = [
            (int(l[0]), float(l[1]), int(l[2]), int(l[3]), int(l[4]), float(l[5]))
            for l in [ln.split() for ln in lines]
        ]

    # retrieve resistance value
    if len(sys.argv) > 1:
        res = int(sys.argv[1])
        print('Resistance: {}'.format(res))
    else:
        res = int(input('Resistance: '))

    # check input
    if res < data[0][2] or res > data[-1][4]:
        print('Invalid resistance')
        exit(0)

    # find two corresponding records in table
    for rec in data:
        if res < rec[3]:
            rec_next = rec
            break
        rec_prev = rec

    # find mid value between two records
    mid = (rec_next[3] - rec_prev[3]) * rec_prev[1] / (rec_prev[1] + rec_next[1]) + rec_prev[3]
    if res < mid:
        rec = rec_prev
    else:
        rec = rec_next

    # calculate temp
    temp = rec[0] + (res - rec[3]) * 100 / rec[3] / rec[1]
    print('Temperature: {:.2f} °C'.format(temp))