DS18B20 error below -10°C

I am trying to control the temperature of a freezer that works between -20°C and -10°C. The problem is that the error curve in the datasheet shows that the typical error from -10°C to +85°C is 0.5 °C.

What is the real error from -20°C to -10°C?

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For this kind of question you are better off asking it from the sensor manufacturer. I don’t think we have any devices using this sensor.

Cleo

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Correct.

Based on my extensive experience with hardware, the “correct” answer is “look at the datasheet for the sensor you want to use.”

First, is it operational below -10° C?  Many commercially rated parts are not rated below temperatures like -10° C.

If your component is not rated for cold temperatures, you may need a different version that is rated for the temperatures you want to use.

If it IS   rated for cold temperatures, the datasheet should give you the calibration curve for the low end.  If it doesn’t, the part may not be rated that low.

If you absolutely MUST  use that part, you can try to create your own calibration curve by comparing it with a known standard.

Fair warning:  Using a device outside its ratings might cause strange and un-repeatable behavior.