SNAP Analog Input Modules
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SNAP Analog Input Modules
PAGE
16
DATA SHEET
Form 1065-140815
Thermistor Input Module 0–400 K (continued)
Auto-range Curves
The following table shows temperatures in °C and °F that
correlate with resistance values in Ohms for the generic curve
types for four popular thermistors using the Steinhart-Hart
equation. Choose the curve type for your application in
PAC Control or PAC Manager when you configure a SNAP-
AIR400K-8 module.
Choose a 2-wire thermistor value with a resistance over the
target temperature range that is much larger than the lead
resistance for your application
Lower value curves (2252 or 3K) work best at cooler
temperatures (< 25 °C or 77 °F) because long lead wire
resistance can add significant errors to the measurement.
SNAP-AIR400K-8 Auto-range Curves Table
2252 curve 3K curve 10K type 3 curve 10K type 2 curve
Temp °C Temp °F Resistance (Ohms)
-40 -40 75,769.0 100,935.0 239,686.0 336,450.0
-35 -31 54,647.0 72,798.0 179,200.0 242,660.0
-30 -22 39,851.0 53,088.0 135,185.0 176,960.0
-25 -13 29,368.0 39,123.0 102,861.0 130,410.0
-20 -4 21,861.0 29,122.0 78,913.0 97,072.0
-15 5 16,429.0 21,885.0 61,020.0 72,951.0
-10 14 12,459.0 16,598.0 47,543.0 55,326.0
-5 23 9,532.0 12,698.0 37,313.0 42,326.0
0 32 7,353.0 9,795.0 29,490.0 32,650.0
5 41 5,718.0 7,617.0 23,457.0 25,391.0
10 50 4,481.0 5,970.0 18,780.0 19,899.0
15 59 3,538.0 4,713.0 15,130.0 15,711.0
20 68 2,813.0 3,748.0 12,263.0 12,492.0
25 77 2,252.0 3,000.0 10,000.0 10,000.0
30 86 1,814.0 2,417.0 8,194.0 8,057.0
35 95 1,471.0 1,959.0 6,752.0 6,531.0
40 104 1,200.0 1,598.0 5,592.0 5,326.0
45 113 983.8 1,311.0 4,655.0 4,368.0
50 122 811.2 1,081.0 3,893.0 3,602.0
55 131 672.5 895.8 3,271.0 2,986.0
60 140 560.3 746.3 2,760.0 2,488.0
65 149 469.0 624.8 2,339.0 2,083.0
70 158 394.5 525.5 1,990.0 1,752.0
75 167 333.1 443.8 1,700.0 1,479.0
