Having a hard time getting a clean working PID tune

ianborg

I switched over to the E3d Revo hot end.
on their support site it indicates the following config changes are needed to use the correct thermistor.
M308 S1 P"e0_temp" Y"thermistor" T100000 B4725 C7.060000e-8

my PID auto tunes take over 30 min and always seem to give warnings, is there something else I need to do?
thanks!

11/6/2022, 9:37:21 PM	Warning: heater behaviour was not consistent during tuning
Auto tuning heater 1 completed after 3 idle and 50 tuning cycles in 2030 seconds. This heater needs the following M307 command:
 M307 H1 R1.456 K0.224:0.291 D2.50 E1.35 S1.00 B0 V24.6
Edit the M307 H1 command in config.g to match this. Omit the V parameter if the heater is not powered from VIN.
11/6/2022, 9:18:28 PM	Warning: heater behaviour was not consistent during tuning
Auto tune starting phase 4, measuring with fan on
11/6/2022, 9:06:44 PM	Auto tune starting phase 3, measuring
11/6/2022, 9:04:59 PM	Auto tune starting phase 2, settling
11/6/2022, 9:03:35 PM	Auto tune starting phase 1, heating up
11/6/2022, 9:03:30 PM	M303 T0 S205

when i try to print i then get this

Heater 1 fault: temperature rising too slowly: expected 0.40°C/sec measured -0.40°C/sec

code_text

deckingman

@ianborg You haven't said what you do when the tuning is complete. Do you edit the M307 in config.g or do you send the result to config_override.g? If it's the former, do you have a different M307 in config_overide.g?

Also, it seems to that there is an issue during phase 4 with the fan running. Have you tried tuning just the heater, rather than the tool? If so, what happens? When tuning with the fan (as a tool) where do you position the print head? Close the build plate or not? Is you part cooling fan too powerful perhaps? You could try limiting the maximum speed and see if that helps.

gloomyandy

@ianborg It might help folks understand what is happening if you post the temperature graph from DWC during tuning (especially the fan on stage). You may need to capture multiple screenshots if it is taking a long time.

ianborg

@deckingman Yes I put it in config.g
I have tried tuning with the bed close and far away, same results
I will try just the heater and post results.
also running latest firmware 3.4.4 (duet 2 wifi)

ianborg

@gloomyandy I will get some screen shots posted asap
thanks!

deckingman

@ianborg said in Having a hard time getting a clean working PID tune:

@deckingman Yes I put it in config.g..............................

OK, that's part of the answer. The second part of the question was "is there another M307 in config_override.g"? If so, this would override the M307 that you put in in config.g which might be part of the solution to your issues. If not then we need to consider other possibilities.

I understand that you to plan to tune just the heater (without fan) and supply the temperature graph during tuning of the tool (with fan) - that would also be useful information.

ianborg

@deckingman no - nothing was in config-override.g file
interesting result tuning just the heater worked and gives no error when printing now.
it also only took a few minutes where the other way was taking 30-60 minutes.
so i guess i'm good now. thanks for the replies.

11/7/2022, 8:31:13 PM	Auto tuning heater 1 completed after 3 idle and 5 tuning cycles in 572 seconds. This heater needs the following M307 command:
 M307 H1 R0.741 K0.195:0.000 D5.31 E1.35 S1.00 B0 V24.6
Edit the M307 H1 command in config.g to match this. Omit the V parameter if the heater is not powered from VIN.
11/7/2022, 8:27:44 PM	Auto tune starting phase 3, measuring
11/7/2022, 8:24:20 PM	Auto tune starting phase 2, settling
11/7/2022, 8:21:46 PM	Auto tune starting phase 1, heating up
11/7/2022, 8:21:41 PM	m303 p1 s200 h1
Auto tuning heater 1 using target temperature 200.0°C and PWM 1.00 - do not leave printer unattended

ianborg

also of note, after having "heater issues" with my revo, i purchased a replacement heater and things seemed to be fine for a while. I had to some noise issues which was the result of a Y bearing rod rubbing. i fixed that and tried to print again and that's where these issues started. so i figured I need to re-calibrate everything, and ended up with this issue I posted about. after thinking it was fixed, i tried some more prints tonight and it really has smelled up my office. i chalked it up to the filament and threw on a known good roll. as I began to extrude 100mm, it was nearly falling out of the nozzle. I then saw the temp jump to 240 c and got a heater fault.. hmm as i touched the wires, yep the temps start moving all over the place.
so I have an issue with the heater, thermistor or wiring. the smell probably was because the filament was being heated way to hot and the temp readings were false. and that also of course explains, why things seemed fine and now all of a sudden all kinds of PID tuning issues.
so i posted this incase anyone finds it helpful in the future.

deckingman

@ianborg As well as your wiring issue, it sounds like your part cooling fan might be too aggressive in that too much air is being directed at the nozzle/heater block. That would explain why you have problems PID tuning the tool, rather than just the heater. Unless you fix that, you could potentially get heater faults when the fan comes on during a print.