calibrate/use unknown temp probes?

[Johannes S]

how would i determine the correct values to enter for unknown temp probes?
i bought some on aliexpress, but didn't notice they were of unknown type. still i would like to use them, as i don't want to dump them.
what do i need to do? didn't find any information in the wiki ....

thanks!

 

[Steve_M]

To calibrate them, you'd need to use a known good probe and take measurements of the unknown probes at 0C, 25C, and 100C. You'll need to measure the unknown probes resistance at these temperatures. From those 3 measurements you can calculate the Steinhart-Hart coefficients.

http://www.thinksrs.com/downloads/programs/Therm Calc/NTCCalibrator/NTCcalculator.htm

 

[Johannes S]

thanks a lot steve.
wish i had a probe to trust i have several of them, from my maverick, and another kitchen termometer and other stuff, but they all show different temps

 

[DavidNP]

to find out which probe to 'trust', you can test which one gives the correct temperature with a water boil temperature test.

Water will boil around 211f.... but depends on your elevation (see chart)

 

[Johannes S]

made the measurements today. interesting to see, that some probes SEEMS to be identical, but vary by several degrees.
i put them in a pot together with a k-type thermocouple and then entered measured resistance value into the calculator. updated the heatermeter config, and all set now.
thanks!