There must be a reference temperature sensor near the "cold junction", where the NiCr-Ni thermocouple wires are terminated. Remark: The external temperature pr

There must be a reference temperature sensor near the "cold junction", where the NiCr-Ni thermocouple wires are terminated. Remark: The external temperature probe is always called "hot", the reference junction always "cold", even if you measure liquid nitrogen with your sensor... If the "cold junction" is just the banana-plugs, then it's obviously not too easy to get a reading of the temperature there. Better devices will use these rectangular thermocouple-sockets (a rectangular block with two small, dissimilar, slots) and have proper NiCr-Ni cabling inside, just up to the termination point on the PCB, right adjacent to the voltage amplifier/sensor for the reference temperature.