calibration

there's 4 settings for calibration

• left TC gain
• left TC offset
• right TC gain
• right TC offset

the formula in code is

left  = (left  * leftgain)  + leftoffset
right = (right * rightgain) + rightoffset
act   = (left + right) / 2

so in theory you should be able to calibrate the oven by running a profile, and dumping the values via serialport, while at the same time measuring with a known good temperature sensor taped to the pcb

here's some code that does that with a Uni-T ut181a

https://gist.github.com/aep/03db148e01796316018ca241f6825d88

remember to set gains to 1 and offsets to zero before doing that, so you can then match the curves in matlab/octave using the above formula

for some reason in reality the offset is different tho. i had to set them to half the value than in matlab to get a good curve. some experimentation is required