MCU reporting incorrect temps
hello, Im not sure if this is a firmware issue but ive had an issue with my control board mcu reporting very high temps. is there a firmware fix or have i fried something?
16 Replies
sometimes the bed and hotend do the same, sometimes not
update, the hotend and bed seem to be displaying the correct temp but when told to heat they dont and eventually time out and kill rat os
this whole issue has come from nowhere btw, earlier today it was behaving fine
Double check you have good connections
I dont see how its a connection thing if the board itself is reporting its temp all crazy like that. Its either some sort of interference, voltage issue or just a bad board. If you disconnect everything from the MCU except the power and the connection to the Pi, does the SKR at least show its correct temperature? Also do you have a volt meter and can double check the power supply is putting out 24v into the board?
Hi, sorry only getting back to this now, was asleep (eu timezones) I don't have a volt meter but will test taking everything out after work. I have the same feeling that it being connections would be unusual but will try it too and report back
A thermistor changes resistance with change in heat. If it has a bad connection to the MCU, then the resistance will be changing, so the MCU will think the temp is changing
But also like chicken said, if you're not getting the proper voltage to the right places, that could also throw it off
Wait, that isn't showing a temp change, it's showing a pwm % change and NO change in the temp. Triple check your connections
I gotta stop reading these tiny pictures on mobile
I agree Tik but one of the temperatures off is the one built into the board. Thats whats whacky. Lets see what lrnc comes back with
Okay, now I'm at my desk and can zoom in properly. Now that I'm looking at it, the board is staying it is 320.4C. That suggests an incorrect thermistor chosen but like you said, its the one built into the board so seems weird. If @Irnc_Isnt_It can supply the config files we might be able to eliminate that
The board isn't showing one number, that's just when I screenshot it, it's fluctuating violently between around 100 and 1000
I'm gonna try a few things when I'm back from work but I have a feeling the boards fucked. Cause it was working fine then all of a sudden it's showing issues
I'll get the config
right, but your room isn't 100C, I don't think an SKR under full load should be 100C at any point either. If it was fluctuating down to room temp at least some of the time, maybe it would be just connection. But we're loking at a wild swing in temp AND an offset to way too high
That pic only has a few minutes worth, but the lowest it looks to go is 300+
Ya exactly, it's also since it's the mcus built in sensor makes me think it's hardware
yeah :/
I'll try reset it then just move to a different board,btt stuff has been really testing my patience recently
Is there a way of disabling the temp sensor? Cause it works fine apart from displaying the wrong temp
even if you could disable it to me that is a sign of a larger underlying issue. I have 3 printers with BTT boards and they are all solid. Not sure whats going on here but I suspect unless its something thats plugged in causing the strangeness you need to get that board replaced. Reach out to BTT and see what they say on sending a new one to you.
ive sent them an email, just gotta wait and see, it really sums up this whole project. the thing is now its showing v high temps but its stable so i have absolutely no idea, as soon as i use any of the 5 or 3.3v or probe pins the thing freaks out, I presume there is a header somewhere inside the thing thats gone bang
yah it sounds like it. Have you unplugged everything besides the Pi?
I would even pop out the drivers if that does not solve it and see if one of those is causing noise on the 3.3v or 5v rail and causing the issues