MK3S hotend/ heated bed current temperature constantly changing/ non stable
Hey guys,
Anyone noticed this ....
My hotend/ bed temp is constantly changing - for example, my Prusa mini reports both as 23 degrees yet the MK3S is changing between 23 - 25 degrees for both readings very second or so.
I'm going to have to admit I've not noticed how long it has been doing this.
I plugged a spare (new) thermistor into the hotend port on the board, same issue. Measured the resistance of the existing thermistor, it was a constant 104.3 K ohm which is spot on within the range it should be. I think clearly with both the hotend and bed temps flucturating it wasn't going to be a thermistor issue as that would have meant both had developed the same issue at the same time, not likely, but does no harm to check.
Kinder presuming therefore this is a firmware 'feature'.
Should add that the printer is printing perfectly, so this appears to be cosmetic.
Kindest regards in advance,
Martin
PID tune?
Have you done a PID tune? That will run tests on the nozzle heating routine to tune it to avoid swings. This is particularly important after making any hotend changes like a thermistor replacement.
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He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
Pid tune
Hi bobstro,
Thank you for your reply.
I didn't run the PID tune (I can do), but as this only seems to be relevant when heating the hotend, I figured it wasn't going to affect the temperature reading when the hot end was off, + the bed temp is showing the same symptoms, which as far as I can tell, is not affected by the PID tuning.
Very odd, I have confirmed with Beth resistance reading and testing a brand new thermistor that the printer should be reading a constant resistance at room temperature, yet the value changes.
Don't recall if PID tune does the bed as well, but you definitely should run it
I don't recall if the Prusa PID tuning does the bed as well as nozzle, but you want to run it for your nozzle in any case. If it picks up the bed, bonus. It only takes a few minutes.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
Pid tune
Very fair point, running it now.
:0)