Bed temp too low?

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zozzle
Posts: 7
Joined: Fri Jul 28, 2017 10:24 am

Bed temp too low?

Post by zozzle » Sun May 13, 2018 5:46 pm

I tried searching the duet forums for an answer, but didn't find anything that was the same.

In the web interface, the bed temp displays at around 14-15 degrees at room temperature. The hotend seems to display a true reading, around 22 degrees. I haven't changed anything, and the thermal grease is still providing a solid contact for the thermistor underneath the bed. How would I go about fixing this? It doesn't seem too severe, but I have no idea if it means the temps become even more skewed once they get higher.

Thanks.

piglet74
Posts: 15
Joined: Sun Mar 18, 2018 9:37 am

Re: Bed temp too low?

Post by piglet74 » Sat May 19, 2018 9:09 am

My new build is the same way. I have not had any issues. I'll check with a thermocouple and meter this afternoon. My thought would be the bed has more surface area so gets generally cool though.

Just now at rest my bed was 11 but hot end was 19.

I had to zero my probe on some ice. My plate is reading 60 during a print. However the PEI and Glass top is about 55. So it might be worth giving it a little extra for losses. Also, I'll check it again when cool now that I calibrated the thermocouple.

piglet74
Posts: 15
Joined: Sun Mar 18, 2018 9:37 am

Re: Bed temp too low?

Post by piglet74 » Sun May 20, 2018 8:56 am

Ok So this morning I started tweaking the thermistor for the bed. It was reading 10deg low. So I kept tweking the m305 command in the config.g from H-97 all the way around to H15. That got me to .3 deg within room temp. Next I'll set it to 60 and see if that moved the upper end.

User avatar
UltiBots
Posts: 592
Joined: Fri Apr 21, 2017 10:18 am

Re: Bed temp too low?

Post by UltiBots » Wed May 23, 2018 1:29 pm

Keep us posted. We have sold several thousand kapton heaters and have not seen a temperature split this large. I would check connectors, continuity and measure the resistance. Maybe ask at forum.duet3d.com.

Also check out:
https://duet3d.dozuki.com/Wiki/Temperature_sensors
https://duet3d.dozuki.com/Wiki/Choosing_a_bed_heater
https://duet3d.dozuki.com/Wiki/Tuning_t ... re_control
Brad - UltiBots LLC

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