Unexpected Thermocouple Measurement With NI-9215

Updated Jul 3, 2018

Reported In

Hardware

  • NI-9215
  • J-Type Thermocouple

Software

  • LabVIEW

Driver

  • NI-DAQmx

Issue Details

I am using a J type thermocouple and I have it hooked into my NI-9215. However, the values I am reading in LabVIEW are not accurate at all. The thermocouple outputs 0 to 5 mV. What should I do?

Solution

The NI-9215 has a 16-bit ADC resolution, and an input range of ±10V. A possible reason that you are getting inaccurate readings in LabVIEW, is due to the fact that the changes in voltage you are trying to read are too small to be detected by the 9215. The solution to this, would be to add in an amplifier between the thermocouple and the NI-9215, reading that voltage, and scaling it back down for processing.

WAS THIS ARTICLE HELPFUL?

Not Helpful