Hello most excellent 3d printing community. I need some help calibrating my new hotend on my delta running repitier.
I run the m303 command at S 250. It takes some time, but it hits 250 3 times and gives me my KP, KI, and KD. I get their average and then save it to my EEPROM.
the issue i seem to have, is no matter what values are determined by PID autotune, my hot end ALWAYS stays below target. T=230 A=227 T=250 A=246 etc. it seems like im always just a little low.
Ofcourse this prevents prints from kicking off. I dont see ANY overshoot during AutoTune and very little occilation.
Ive adjusted my PID_MAX for EXTR 1 so hotend is pulling as much power as it can, but for some reason it doesnt want to hit the target. Anyone know what values I should check out to get this undershooting problem resovled?
Thanks in advance for helping.
first arc to 250 is Auto Tune, next two are trying to get to 230 with new Kp Ki and Kd from first autotune.
Something about your integral action is off. Look for settings where it might be zero somewhere?
Like Ki? Or something else called integral action?
Ki is the integral gain. So yeah, look at Ki, integral max, stuff like that.
Lemme pull up the Repetier PID code… haven’t looked in a long time…
OK I’ll check that out now.
In configuration.h, check:
EXT0_PID_INTEGRAL_DRIVE_MAX
EXT0_PID_I
EXT0_PID_MAX
Then make sure you’re properly flushing/setting EEPROM.
whats the proper procedure for flushign settings? i got octopi with eeprom editor, i load, change, and save. seems to take my changes.
When you run autotune, are you putting the settings back into EEPROM?
yup, and making sure i save, then i load aging to make sure they stuck.
i bumped Extr.1 PID drive max from 180 to 200 and now target is 230 and actual is 228.3 so seems like im getting closer. I wonder if i need to bump my Ki a bit. its 2.5 right now and I dont have any over shoot.
What heater wattage do you have? You should set all the maxes to 255, then dial back from there.
PID MAX is 255. i think my hot end is 40 watts.
i bumped pix drive max from 200 to 220 and ki from 2.5 to 3.0 and now Tis 230 and A is 229.8. seems like its going the right driection. but ive got to turn up so many values 
i dont want to burn this thing out 
You shouldn’t need 40 watts to maintain 230C unless you’ve got a big fan pointed directly at the hot end and it isn’t insulated.
What color are the heater cartridge wires? Red is usually 40w, blue means 25w. If you have a 25w heater, you’re probably going to need to set all your maxes to 255 (ie 100%).
red, its a HE280 from seemecnc, I think the hot end fan is blowing alot of air on the heat sink. ive got a feeling the hotend is fighting that fan. but there isnt any way to dial it back
Airflow on the heatsink is great, that shouldn’t be causing issues. I’m thinking more like a print cooling blower fan pointed at the hot block.
For now, just set all your maxes to 255, there’s zero harm in running the hotend at the full 40w. Then once you’re maintaining temp and stable, check your actual heater power via Repetier Host. If it’s running >200 at steady state, you have to ask why it’s taking so much juice to keep your hot end hot. (Could be an off-spec cartridge with resistance too high, for example.) If it’s running more like 100-150 at steady state, but was having trouble maintaining temp, then that gets you back to a settings issue somewhere.
cool is there a Mcode for checking heater power?
layer fans are all off im just hitting this in the home position.
Excellent! I boosted max drive to 255. hot end over shot 230 by 2 deg C and is now T 230.0 A 230.1! gonna try to keep this and see how it prints. thanks for the help!
No problem. You might consider checking the heater cartridge resistance and PSU voltage with a multimeter to see if it’s under-powered for some reason.