Idle Temperature too high (>30°C)  

Re: Idle Temperature too high (>30°C)

Am i really the only one whose hotend and bed temperatures read ~10°C above the actual room temperature?

Re: Idle Temperature too high (>30°C)

My MK2 shows temperatures about +7°C too high, both for bed and nozzle temp.

I haven't had any issues printing with it, i did lower my temps slightly however.
On the MK2 I usually print PLA at 200°C and my heatbed at 55°C (depends on the brand), on my Ultimaker i use 205/60 for the same filament

Re: Idle Temperature too high (>30°C)

working with temp probe for my PC (liquid cooling) i know i have to calibrate them because i can have 5 degres delta... and the temp range is not 0-300° but more 0-130°
I did not received mine yet but is there any calibration on the temp probe in the firmware ???

Re: Idle Temperature too high (>30°C)

I have to increase both the hotend and bed temperature by 10°C now to get good prints, because if i print with the default Slic3r profile for e.g. PLA, the bed heats to effectively only 45°C, and the lacking adhesion on the PEI sheets ruins basically any print then.

So setting the bed to 65°C and the hotend to 225°C for the first and 215°C for the other layers creates perfect prints, but this is quite annoying as i experiment with multiple slicers and profiles, and i'd like to just keep the recommended/stock profiles to compare.

Re: Idle Temperature too high (>30°C)

I have the same issue with both the hotend and bed temperatures. For me they are ~9 C too high. I contacted support and they asked me to send them a video of the issue.

Re: Idle Temperature too high (>30°C)

I think the 30°C are just the lowest Temp the firmware is showing.

My bed is quite accurate in the set and measured (IR term) above 40°C or so.

Carsten

Re: Idle Temperature too high (>30°C)

💡 it must be related to the ports at the rambo board ❗

i've just build a 2nd printer and used some genuine prusa i3 mk2 spareparts, including the original MK42 heatbed with its temperature sensor.

➡ instead of a minirambo it uses a ramps1.4 with mega 2560 processor board. i compiled the firmware release 3.0.10 for my board and kept the settings for the heatbed sensors 1:1 (changed only the one for the hotend, which is a Hisens 3950 type at my replica (type 13 instead of 5)).
both printers are located in the same room.
the genuine i3 mk2 shows 31°C (both hotend & bed), while my clone shows 24° (again: both, hotend & bed). my room thermometer shows 24°C as well.
😕 so i bet that there is something fishy with the pullup resistors at the minirambo design.
🙄 but this should mainly affect low temperatures. at higher temperatures the resistance of the thermistor is much lower... so the temperature error will be diminished as well.

Re: Idle Temperature too high (>30°C)

but this should mainly affect low temperatures. at higher temperatures the resistance of the thermistor is much lower... so the temperature error will be diminished as well.

Thanks, Jeff! Yep, this appears to be it. I was worrying about the (in my case) 6 degrees off at room temperature, but I've confirmed (using an IR thermometer to measure the heatbed temp) that at both 55 and 100 degrees the actual temperature is quite close to the reported temperature. I do see a several-degree difference at various spots on the heatbed, but the average is very close to the reported temperature.

-Ticc

Re: Idle Temperature too high (>30°C)

This issue just appeared for me. Temperatures were accurate prior to a big print. Noticed it after a big print fail. Both nozzle and bed now read 30C when RT was actually 22-23 (previously the reported temperatures were accurate). However, this also occurred coincident with performing Autotune PID for both nozzle and bed via Pronterface. Will likely reset to factory default and see if problem persists.

Re: Idle Temperature too high (>30°C)

I recently purchased a mini Rambo 1.3a directly from ultimachine, and was seeing the same issue, my idle temperature was too high. I contacted them directly and they informed me that their board has a voltage gate on the thermistors that prevents it from reading too low of a temp/too high of a voltage. The ~30 degrees idle temp is normal and doesn’t affect the higher temperature readings. Using a laser thermometer, I compared the bed on my printer that was reading too high with my old Mk2.5 sitting right next to it, and that was the case - only the lower temperatures were affected. Everything else was pretty much spot on.