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Heatbed low temperature reading

Posted by PeterLim

PeterLim

Heatbed low temperature reading
September 08, 2014 01:22AM

Registered: 9 years ago
Posts: 5

Hi all. I'm using NTC140 thermistor. However i'm not able to have a accurate reading on my repetier. It's shows a reading of 1.8 degree when the room temperature is 27 degrees.
Is my selection of thermistor correct in my marlin? Hopefully someone is able to help.

s882.photobucket.com

This is the thermistor I am using.

s882.photobucket.com

Edited 2 time(s). Last edit at 09/08/2014 01:29AM by PeterLim.

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UkIan

Re: Heatbed low temperature reading
September 12, 2014 04:17AM

Registered: 9 years ago
Posts: 376

You can change the thermistor setting in the firmware without risk, so if no one recognises the thermistor you can step through each option without fear of frying something.

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Traumflug

Re: Heatbed low temperature reading
September 13, 2014 05:38AM

Registered: 13 years ago
Posts: 7,616

You have to know the exact type. "104" likely means a 100k thermistor, but there are many of them with different Beta values. Also temperature readouts at room temperature aren't very exact.

Third, check the comparing resistor. 4700 ohms is the standard, but there are also boards with an 1000 ohms one. 1000 ohms gives more accuracy at higher temperatures.

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