©
National Instruments Corporation
9
TB-2605 Isothermal Terminal Block
Figure 7.
Analog Bus Connector
Cold-Junction Temperature Sensor
The TB-2605 temperature sensor voltage output varies from 198.54 mV to
19.58 mV over the temperature range 0 to 55 °C, respectively, and has an
accuracy of ±0.5 °C over the 15 to 35 °C temperature range and ±0.9 °C
over the 0 to 15° and 35° to 55 °C temperature ranges.
1
You can use the following formulas to convert the cold-junction sensor
voltage to cold-junction temperature:
T(°C) = T
K
– 273.15
where T
K
is the temperature in kelvin
a = 1.295361 x 10
-3
b = 2.343159 x 10
-4
c = 1.018703 x 10
-7
R
T
= resistance of the thermistor
V
TEMPOUT
= output voltage of the temperature sensor
1
Includes the combined effects of the temperature sensor accuracy and temperature difference between the temperature sensor
and any screw terminal. The temperature sensor accuracy includes tolerances in all component values, the effects caused by
temperature and loading, and self-heating.
AB1+
AB0+
No
Connection
No
Connection
No
Connection
No
Connection
AB1+
AB1–
AB1–
AB0+
AB0–
AB0–
T
K
1
a
b
R
T
ln
(
)
c
R
T
ln
(
)
3
+
+
[
]
---------------------------------------------------------------
=
R
T
189
K
V
TEMPOUT
2.5
V
TEMPOUT
–
----------------------------------
⎝
⎠
⎛
⎞
=
T
°
F
( )
[T(
°
C
) ]
9
5
------------------------
32
+
=