Solution
Technically, thermocouples produce very small voltages and can act as antennas, making the readings highly susceptible to surrounding noise.
The mioDAQ is a multifunction DAQ device not specifically designed for temperature measurement using thermocouples. To reduce noise, you’ll need to apply a low-pass filter—either in software or through external circuitry.
If you're using FlexLogger Professional, you can implement a software-based low-pass filter using the Calculated Channels feature. Applying a 4 Hz low-pass filter helps eliminate high-frequency noise, resulting in more stable and consistent readings, as shown in the image below.
If you're using FlexLogger Lite, low-pass filtering isn't available in the software. To reduce noise, you'll need a dedicated temperature measurement DAQ device with built-in filtering, such as the NI 9210.