National Instruments SCC-TC01 用户手册
© National Instruments Corporation
7
SCC-TC Series Thermocouple Input Modules User Guide
You can use the following formulas to convert the cold-junction sensor
voltage to cold-junction temperature:
voltage to cold-junction temperature:
where T
K
is the temperature in kelvin.
where
a = 1.295361
× 10
–3
b = 2.343159
× 10
–4
c = 1.018703
× 10
–7
R
T
is the resistance of the thermistor in ohms.
where V
TEMPOUT
is the output voltage of the cold-junction sensor.
where T(°F) and T(°C) are the temperature readings in degrees Fahrenheit
and Celsius, respectively.
and Celsius, respectively.
Note
V
TEMPOUT
varies from 1.91 V (at 0 °C) to 0.58 V (at 55 °C). For best resolution, use
the maximum gain for this range on the analog input channel.
For the cold-junction sensor measurement accuracy, refer to the
Uncompensated Connectors and Accuracy
If you are using an SCC-TC02 with an uncompensated SCC panelette,
temperature gradients between the module and the junctions on the
panelette affect the accuracy of your measurements.
temperature gradients between the module and the junctions on the
panelette affect the accuracy of your measurements.
T
°C
( )
T
K
273.15
–
=
T
K
1
a b
R
ln
T
(
) c
R
ln
T
(
)
3
+
+
[
]
--------------------------------------------------------------
=
R
T
5 000
V
TEMPOUT
2.5 V
TEMPOUT
–
--------------------------------------
,
=
T
°F
( )
T
°C
( ) ]9
[
5
------------------------
32
+
=