Solution
1. Ensure the thermocouple is wired correctly. Refer to a thermocouple color code guide to see wiring specifications.
2. Refer to the specific module's Getting Started Guide to verify wiring considerations.
3. Refer to the Unexpected Voltages, Floating or Crosstalk in Analog Inputs document. Specifically, NI does not specify what the device will read for an unconnected channel. Ensure that you are measuring a connected channel.
4. If you are still reading unexpected voltages or temperature, refer to this thermocouple measurement tutorial.
5. Ensure that the voltage range you are measuring is within the specification of the device. For example, the range of the 9213 is +/- 78 mV. Check for the voltage with a multimeter and check for a module that can accommodate it.
6. If you are using a cRIO with a NI Thermocouple Module and have selected the K-type in the project, make sure to deploy the module settings, if readings are still incorrect try rebooting the cRIO.