Do NI 9212 and TB 9212 Only Apply the Cold Junction Compensation for 2 Channels?

Issue Details

Reviewing the NI 9212 Datasheet , TB-9212 has only 2 internal cold-junction compensation channels.

Solution

NI 9212 applies Cold Juntion Compensation for its 8 Channels.
The module used in conjunction with TB-9212 (Isothermal Terminal Block) has two internal CJC channels :
CJC 0—corresponds to thermocouple input channels TC0, TC1, TC2, and TC3,  
CJC 1—corresponds to thermocouple input channels TC4, TC5, TC6, and TC7  

When you specify that the CJC source as "Built in" on the DAQmx Create virtual channel, the software will consider the CJC channel which corresponds to the TC input you're using.  
Samples are acquired simultaneously from CJC and TC channels at each clock cycle, then processed by the software (DAQmx driver) in order to remove the unwanted voltages.  

Here you have the details: NI 9212 (FPGA Interface)