Fluke Tir32 continuous (re)calibration ?

[darkstar49]

Hi,

my TIR32 works more or less OK, temps seem OK (things from the freezer, boiling water, etc...), but every 30 secs or so, it freezes and says 'calibration' for a few seconds, and then works fine again...
I think to recall having seen similar behaviour on Fluke thermal cams of similar generation (Ti25,...), but not at this frequency.

It doesn't make the cam unusable, but it's somehow annoying.

I asked Fluke about their calibration: 710€ or 1065€ (excl. VAT), for a CALNET vs. CALINTL calibration respectively (flagged as 'ISO9001 traceable' for the first, and 'Accredited' for the 2nd ??).

Not being even sure that a calibration is gonna fix the issue, that's sounds quite a lot to me...

Any thoughts/suggestions ?

[railrun]

Does the intervalls get longer when the unit is on for a while?
I don‘t have one, but this is the internal calibration with a shutter. At the beginning the device warms up and it compensate the temperature drift. After a few minutes the temperature should be stable and it need less calibrations.

[DaJMasta]

Depending on how much access you have to the configuration, usually there are two methods they use to trigger NUC calibration - either a certain amount of change in temperature of the core, a certain number of frames taken, or both.  As previously mentioned, if the interval gets longer over time when the camera is operating, it's probably the delta temperature method - as the core warms up to its equilibrium point, the change slows and the interval gets longer.  If it's a fixed timeframe, it's likely just counting a thousand or two frames and then automatically rerunning the calibration.  A hybrid of the two is probably most useful (recalibrate after a certain temperature change or after a large number of frames), and they are likely just values in configuration firmware, but I don't know if every system will actually give you access as the user.

This behavior doesn't have to do with the radiometric calibration units get to read out temperatures correctly.