extruder temp is reported wrong. phatus rapido uhf
I just did a 38h long print and now after cooldown to 23C my printer says that extruder temp is 51c. So i took the toolhead apart and hot-end is cool to touch. If i take it to my hand and let it warm up, reported temp increases as expected. So i took out my multimeter and check the residence: 102kOhm at 23C. If i look at the datasheet, it checks out. What can i do?
10 Replies
is it correct at the temperature you set? If so, don't worry about it, thermistors are inaccurate at lower temps
As far as i tested, no. I set it to 250c to extrude abs, extruder struggled until increased the temp to 270.
at 250c, did you use another thermometer to verify temp?
No I didn’t. Only thing i saw is that it won’t extrude till 270c according to the thermistor.
Abs usually is extruded anything above 220C in my experience.
Is it possible that something in printer config file is wrong?
I took a thermometer (for measuring body temperature) and if i set the temp to 70C and thermometer says 40~41C feels like it has 28-30C offset.
Is this behavior common for failing thermistor or is this something else?
thermistors don't really start to fail. They just measure resistance, which is really simple
Should i just somehow create an offset in firmware? What should i do?
I do not have any temperature fluctuations or whatnot so I don’t think it would be a bad cable either.
Right?
I would not. I would contact whoever you bought it from and talk to them about it
I bought the rapido from ratrig.com
then I would contact them (this is a unofficial discord)
Alright I understand. Thank you!
This might not be the ideal solution but i ended up changing the pull up resistance to 18kOhm and now it works fine. I checked with another thermometer and it’s accurate to a 1~2 degree C at printing temperature.
Update. Found out that the real cause of problems was the thermistor pin on my btt octopus 1.1 so I switched it to another one and now it works flawlessly with old pullup resistanse of 4700