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measuring and writing thermistor table

Posted by ansiomatic 
measuring and writing thermistor table
July 16, 2014 12:15PM
hi, i want to calibrate the shit out of my thermistor to rule out bad temp as a possibility for an issue i'm having.
How could i do this? but more importantly, what's the best way to measure the temperature? Is an IR thermometer good enough? How could i know if my IR thermometer is correctly calibrated? I know that IR thermometers read infrared light and estimate the temperature with this reading, but i don't know any known fixed temperature standard upon which i could point my IR thermometer and calibrate like regular mercury/gas thermometers calibrate with freezing/boiling water..
Many thanks for anyone who can help me!
Re: measuring and writing thermistor table
July 16, 2014 12:16PM
oh, also, i mistrust my IR thermometer because it varies so much depending on where i point it... my guess is to search for the highest temp and keep that one?
Re: measuring and writing thermistor table
July 17, 2014 05:11AM
If you mean your extruders' thermistor, IR thermometers won't work anyways, as heater blocks are too small. You'd measure a lot of the background, too.

The freezing/boiling water strategy would work for thermistors as well. Just keep in mind water boils below 100 °C if you live more than a few meters above main sea level.

Other than that you need a more precise thermometer.

What are the hassles? Common assumption is, the absolute value of the thermistor doesn't matter much as long as temperature is held. Your filament won't care wether the display reads 240 °C or 250 °C as long as it gets the actually needed heat. Required temperature also heavily depends on the particular material, so there's almost no way around experimenting on how it prints best.


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Re: measuring and writing thermistor table
July 17, 2014 06:08AM
I would check for an online table generator as Epcos provides:
[www.epcos.com]
Re: measuring and writing thermistor table
July 19, 2014 09:53AM
you're probably right.. i'm just moving too close sometimes to the max temp emergency turn off, but i could just raise that threshold.
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