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Principles of Operation
6.3.1.7
Table of Constants
Common thermistors and the appropriate calibration constants for the
temperature range -20 C to 50 C are listed in Table 9. The Model 6100
uses the BetaTHERM 10K3 thermistor values by default.
Manufacturer
BetaTHERM 10K3
BetaTHERM 0.1K1
BetaTHERM 0.3K1
BetaTHERM 1K2
BetaTHERM 1K7
BetaTHERM 2K3
BetaTHERM 2.2K3
BetaTHERM 3K3
BetaTHERM 5K3
BetaTHERM 10K3
BetaTHERM 10K4
BetaTHERM 30K5
BetaTHERM 30K6
BetaTHERM 50K6
BetaTHERM 100K6
6.3.2
AD590 and LM335
6.3.2.1
General
The 6100 uses two constants (C1 and C2) for calibrating the two linear
thermal sensing devices, the AD590 and the LM335. C1 is used as the zero
offset value, and C2 is used as the slope or gain adjustment. Therefore, C1
has a nominal value of 0, and C2 has a nominal value of 1 when using the
AD590 or LM335. In order to calibrate a linear sensor device, the sensor
must be operated at an accurately known, stable temperature. For example,
the sensor may be calibrated at 0 C if the sensor is placed in ice water until
its temperature is stable. A highly accurate temperature probe, thermometer,
environmental chamber, etc., may also be used to determine the known
temperature for calibration.
6.3.2.2
AD590 Sensor
The AD590 is a linear thermal sensor that acts as a current source. It
produces a current, i, which is directly proportional to absolute temperature,
over its useful range (-50 C to + 150 C). This nominal value can be
expressed as:
C1 * 10
1.129241
1.942952
1.627660
1.373419
1.446659
1.498872
1.471388
1.405027
1.287450
1.129241
1.028444
0.933175
1.068981
0.965715
0.827111
Table 9
Thermistor Constants
i = 1 A / K
-3
-4
C2 * 10
2.341077
2.989769
2.933316
2.771785
2.682454
2.379047
2.376138
2.369386
2.357394
2.341077
2.392435
2.213978
2.120700
2.106840
2.088020
123
-7
C3 * 10
0.877547
3.504383
2.870016
1.999768
1.649916
1.066953
1.051058
1.012660
0.950520
0.877547
1.562216
1.263817
0.901954
0.858548
0.805620
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