© National Instruments Corporation 7 USB-9211/9211A User Guide and Specifications
Wiring the USB-9211/9211A
The USB-9211/9211A has a 10-terminal, detachable high voltage screw
terminal enclosure that provides connections for four thermocouple input
channels. Each channel has a terminal to which you can connect the
positive lead of the thermocouple, TC+, and a terminal to which
you can connect the negative lead of the thermocouple, TC–. The
USB-9211/9211A also has a common terminal, COM, that is internally
connected to the isolated ground reference of the module.
Caution The high voltage screw terminal backshell must be installed when using
hazardous voltages (>42.4 Vpk, 60 VDC).
If you are unsure which of the thermocouple leads is positive and which is
negative, check the thermocouple documentation or the thermocouple wire
spool. If you are using shielded wiring, connect one end of the shield to the
COM terminal.
Figure 6. Connecting a Thermocouple Input Signal to the USB-9211/9211A
Thermocouple
TC–
TC+
Shield
USB-9211/9211A
COM