Panasonic FP-X0 L40MR - Page 28

2.4.4 Thermister Input
Connect a thermister and resistor to the analog input connector externally to load the change in the
resistance values of thermistor as analog input values.
Circuit diagram
- Do not connect anything with the 5/6 and 7/8 pins.
- It is recommended to use approx. 2 kΩ as external resistance.
Thermister resistance and digital conversion value
- Use the following formula to convert the thermister resistance and digital conversion value.
- Digital conversion values vary between K0 and K1012.
1012 x R (kΩ)
Thermister resistance (kΩ) = ―――――――― − R (kΩ)
Digital value + 1
Connected thermister
[Example] R = 2.2k
Ω
- Thermisters whose resistance is between 200 and 75kΩ can be used.
Type of thermister (B constant)
Reference of measuring range (°C）
3390K
-50 to +100
°
C
3450K 50 to +150 °C
4300K
+100 to +200
°
C
5133K +150 to +300 °C
Thermister measurement temperature - A/D conversion table
[Example] Thermister B constant : 3450K, external resistance: R=2.2k
Ω
Temperature (°C)
Thermister resistance (kΩ)
Digital value after conversion
50
4.3560
344
60 3.1470 421
70
2.3170
497
80 1.7340 573
90
1.3180
640
100 1.0170 690
110
0.7940
752
120 0.6277 797
130
0.5017
834
140 0.4052 865
150
0.3305
890
Note) The digital value does not include (Total accuracy of A/D converter with built-in microcomputer:
±5LSB) + (Thermister accuracy).
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