What math is performed in the T7-Pro for thermocouple calibration? Interpolation table? Piecewise fits?Can you give the actual equations? I'd like to be able to account for what's happening to the data between input and output. Calibration methods are almost always inexact to some extent, and knowledge of the method improves understanding of the results.
can be a useful factor in understanding the results.
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The T7 uses piecewise polynomials for both direct and inverse calculations. Direct is used to calculate the CJC voltage. That voltage is then added to the measured thermocouple voltage. The sum is used in the inverse polynomial to calculate the final temperature.
Using T7 pro with thermocouples, Kipling, and LJLogM. Example, set AIN13 to type T thermocouple and choose C or F temperature and connect an LM34 to AIN12 for cold junction sensing. When left in the mode that uses the T7 internal temperature for cold junction compensation, the system reports calibrated temperature for the thermocouple channel. If instead I set the AIN13 extended function choices to use "external LM34 on AIN12", the system reports AIN13 N/A F or N/A C or N/A K instead of showing the calibrated thermocouple temperature value. I tried applying a slope value to the AIN12 LM34 measurement, to obtain temperature in F, which worked for AIN12 but didn't solve my AIN13 thermocouple issue. What do I have to do to use the AIN12 and external LM34 CJC method for thermocouple calibration?