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©
National Instruments Corporation
11
TBX-1303 32-Channel Isothermal Terminal Block
Temperature Sensor Circuit Diagram
Use the circuit diagram in Figure 5 for optional information and more
details about the TBX-1303 temperature sensor.
Figure 5.
Temperature Sensor Circuit Diagram
Configuring the Resistor Networks
The TBX-1303 has a pull-up resistor connected between CH+ and +5 V
and has a bias resistor connected between CH– and chassis ground. These
resistors help detect open thermocouples by detecting module amplifier
output saturation. The TBX-1303 ships with 10
Ω
and 10 M
Ω
resistor
networks. Depending on the SCXI module you use with the TBX-1303,
you might need to change from the default 10
Ω
configuration to the 10 M
Ω
configuration. Figure 6 shows how the pull-up and bias resistors connect to
the CH± inputs.
4.7 k
1%
5 k
0.1%
1
2
1
2
2
+
5 k
at 25
°
C
10 µF
16 V
0.1 µF
0.1 µF
–t
°
+5 V
2.5 V
LM 4040
2.5 V
0.1%
MTEMP
DTEMP
W1