Hi all. Can some one help me with problem to start heating/pid values?
I do normally auto pid tuning. Everything goes ok, i save them with M500 command.
After that i start normal printing (slic3r gcode file (240C hotend temp)) hotend start rising but leave 1-2degrees under setpoint and “never” reach that setpoint. I wait many minutes but dont reach that setpoint.
After that i shutdown and put manually on octoprint 240C to hotend and everything work perfectly.
Can anyone tell me what is problem. Under you see screenshot same situation what i explain here.
Try to allready do that. But i dont understand why pid settings works perfectly if i manualle put 240C setpoint. And when gcode file give that same 240C setpoint printer newer reach that temp.
Not can be pid problem i think, because then that manually setpoint not reach that setpoint eather
your gcode starts from a lower temperature than your “working” runs. Increase P by 10% and see what happens. Hypothetically, the I term should make it get there eventually but with such a low delta it WILL take ages. The PID autotuner seems to really like choosing numbers that cause this to happen, changing them for a little overshoot is vastly better than the “perfect” asymptote that autotune goes for.
Also try latest edge, I believe some hysteresis stuff was added at some point. If not, it should be added - something like if temp is within target +/- 3°C for 10 consecutive seconds, call it good and continue
not understand why gcode get wrong temps. because printer shows right temparatures on printer screen (if i put that setpoint manually or gcode put that, same 240C seems on printer screen setpoint, but gcode situation that not be reach).
I try to but 10% and more P. I but very much more P, but not help. Control start oscillate what is normal when put too much P. but after all that i see that setpoint newer reach and pid control not even try to reach that, that only oscillate both sides that 238C. Seems that somewhere printer think that setpoint need to 238C and not 240C (printer own screen tells that right 240C setpoint, but newer reach that.).
That last point is very good, nowadays this firmwares look too exact temp before they start printing that +/- 3°C or 2 is okay.
“For manual adjustments:
if it overshoots a lot and oscillates, either the integral gain needs to be increased or all gains should be reduced
Too much overshoot? Increase D, decrease P.
Response too damped? Increase P.
Ramps up quickly to a value below target temperature (0-160 fast) and then slows down as it approaches target (160-170 slow, 170-180 really slow, etc) temperature? Try increasing the I constant.”
I know autotune not use PID, but manually set setpoint use. And that work perfect, but gcode setpoint not.
I can try to increase I, but that seems to nothing pid tunes helps, because control try to keep up that 238 not 240C what is asked.
And when you put manually 240C that goes there just right and keep there. But when gcode but that same temp that always leave that 238C (2degrees under setpoint).
Same problem is still standing. Again try to heat my printer and have same problems with smoothie. Everytime when i use gcode printer leave 2degrees under setpoint. If i put octoprint manually 250degrees that works perfectly. Like that works perfectly if i put manually my printer display 250degrees. but when gcode goes, not matter what gcode i put that always leave 2degrees below setpoint and go HALT if i wait longer time.
Here we see that same problem again. Now i drive autotune again.
First period is normal printing what have 255degrees printing temp like see in diagram. Temp not go on setpoint ever that goes direct line if wait more and more.
Second period is right after ALL SAME SETTINGS. I put manually on octoprint user panel 255degrees to setpoint and again magic happens. Temps goes setpoint just fine. missing/deleted image from Google+
