Camera thermistor calibration
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Hello I have recently installed a thermistor to measure the temperature of my camera and control its maximum temperature with a fan, but testing the thermistor has a deviation of 6 degrees down, could I somehow calibrate this deviation? Thanks
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What type of thermistor is it?
What values are you using for it?
What temp range are you trying to measure?There's no way to add a temp offset right now.
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It is a thermistor e3d 104gt, this is the configuration line "M308 S2 P "e1_temp" Y "thermistor" A "Chamber" T100000 B4725 C0.0000000706 R4700 ", the temperature range that I want to measure is room temperature-50ºC.
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That temp range may be a bit low to get accurate results. It's geared towards the 180+ temp range of a hot end.
You can try changing the B value I think. If you have a reference source to calibrate with. Like a cup of hot water and a thermometer. Adjust B until the reading matches the thermometer.
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@Phaedrux I hate to argue with you, but this is the wrong approach.
Adjusting beta sets the tracking over wide ranges; adjusting r0 (the 100000) sets the value over a narrow range near a known temperature, such as near room temperature. It is really hard to get 6 degrees off, though, with a thermistor near room temperature! I wonder if there is something else wrong.
Check the thermistor with an ohmmeter. It should, at normal (20C) room temperature, be about 130k (since the 100k specification is at 25C). Note that the temperature coefficient is almost -6%/C, so to be 6 degrees off means the resistance would have to be 36% (or so) off. That would be a huge error.
Put a known 100k resistor across the thermistor input of your board, and see if it says 25C. If not, the input on your board may have a problem (maybe the bias resistor isn't 4700 ohms, due to a bad board or something).
@Mrnice31 set the 'c' coefficient to zero. That is only needed over very wide temperature ranges to get better tracking. You should be fine with just r0 and b.
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@mendenmh said in Camera thermistor calibration:
I hate to argue with you, but this is the wrong approach.
Really? Most people seem to enjoy it.
I'm not a thermistor expert by any means so I could be way way off.
