TBX-1328 Installation Guide
12
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In LabVIEW, you can use the Convert Thermistor Reading VI in the
Data Acquisition»Signal Conditioning
palette. If you are using
Measurement Studio or NI-DAQ, use the
Thermistor_Convert
function. The VI takes the output voltage of the temperature sensor, the
reference voltage, and the precision resistance and returns the thermistor
temperature.
Alternatively, you can use the following formulas:
T
(
°
C) =
T
K
– 273.15
where
T
K
is the temperature in degrees kelvin
a
= 1.295361
×
10
–3
b
= 2.343159
×
10
– 4
c
= 1.018703
×
10
–7
R
T
= resistance of the thermistor in ohms
V
TEMPOUT
= output voltage of the temperature sensor
where
T
(
°
F) and
T
(
°
C) are the temperature readings in degrees Fahrenheit
and degrees Celsius, respectively.
Note
Use the average of a large number of samples to obtain the most accurate reading.
For example, sample for 1 second and average all the samples. Noisy environments require
more samples for greater accuracy.
T
K
1
a b
R
T
ln
(
)
c
R
T
ln
(
)
3
+
+
[
]
--------------------------------------------------------------
=
R
T
5,000
V
TEMPOUT
2.5
V
TEMPOUT
–
--------------------------------------
=
T
°
F
( )
T
°
C
( )
[
]
9
5
-----------------------
32
+
=