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National Instruments Corp.
5
NI 9213E Operating Instructions and Specifications
You can connect thermocouple input signals to the NI 9213E.
Connect the positive lead of the thermocouple to the TC+ terminal
and the negative lead of the thermocouple to the TC– terminal. If
you are unsure which of the thermocouple leads is positive and
which is negative, check the thermocouple documentation or the
thermocouple wire spool.
The NI 9213E also has two common terminals, COM, that are
internally connected to the isolated ground reference of the
module. If you are using a shielded thermocouple, connect COM
to the shield and the shield to a common-mode voltage reference of
the thermocouple. A common-mode voltage reference is a voltage
that is within ±1.2 V of the common-mode voltage of the
thermocouple. If you are using a floating thermocouple or a
thermocouple within ±1.2 V of earth ground, connect COM and the
shield to earth ground. The shield grounding methodology can vary
depending on the application. Refer to Figure 3 for an illustration
of a typical shielding configuration.
