I have a multimeter with the following temperature accuracy for its Type K probe
±3% of reading ±5C
The display is in steps of 1C
I attempted some calibration:
- In ice water, the reading is 0C
- In boiling water, the reading is 94C (1012.9mbar/100C)
Can I interpolate that? Would the reading at 20C be 0.2 x 94C = 18.8 C, i.e. "19" or maybe even "18"? Or are there other factors at play?
I would expect the readings to be monotonous against the actual values, but perhaps the ADC's step size and non-linearity, in combination with the display's granularity, make readings not strictly monotonous, leaving scattered "pleateaus" of readings.
Of course, one could mix the 0C water and 100C at various ratios to create a actual vs. reading chart, but not only is this tedious, I am sure also fraught with systematic and random errors. So I'd rather go with the wisdom of the group here.
The model is "DMR-6500", but perhaps the validity of your reasoning will be independent from the model/brand.