Problem with autotuning hot end after upgrade to v1.19

David J

Note: This was posted on the RepRap forum, but I was advised to post it here…

Setup:
Duet 0.6 board that was running successfully on v1.17e.
E3D v6 hot end (genuine!)

Problem:
Upgraded to 1.19 this morning, worked through the release notes and everything seems good - apart from when I try to autotune the hot end. It keeps coming back with the dreaded "Auto tune cancelled because target temperature was not reached". The command I used was

M303 H1 S250

I get the error as it approaches around 230C - 240C, even though I'm watching the temp steadily increasing right up to that point. I have also sent a separate command to set the temp to 280C and it achieved that without problems (although I did quit at around 270C).

I have tried sending

M307 H1 D60

as suggested in the documentation, but I still get the error.

I suspect that I'm doing something wrong - guidance would be appreciated!

UPDATE: M303 H1 S230 worked OK. Strange…

dc42

I guess that either you have previously set the PWM less than 1 in your M307 command, or the hot end is a little under-powered. You can fix that by putting a silicone sock on it.

David J

The answers are -
1. I hadn't set the PWM to less than 1 in the past (whatever the default is - I have never set it directly)
2. The hot end has the standard E3D heater (25W?). Good enough up to now.
3. The heater block already has an E3D silicone sock on it.

As I said above - what puzzles me is I can see the temperature climbing steadily up to the point where it fails (it's not slowing down just before) and the heater is powerful enough to take the hot end up to its maximum of 280C in good time.

Is the error the result of a time limit (reach the target temp within x seconds), a progress limit (must achieve a specified heat increase per second) or a combination of the two?

dc42

There is a timeout of 5 minutes to reach the target extruder temperature. For a bed or chamber heater, it's 20 minutes.

David J

What are the consequences of performing the achievable M303 H1 S230 command, and occasionally running the hot end up to, say, 250C? Normally I only go up to 230C for ABS, but I may want to go higher now and then.