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PID autotune fail: temp to high

Posted: Sat Dec 05, 2015 9:08 pm
by Penged
I finished my build this evening and when I attempted to run the PID autotune for the hot end it climbed up to 220 and then bailed out saying the temp was too high. After searching the forums I tried raising the temp to 220 but it did the same thing after rising up to 240 this time. Im afraid to try raiding the autotune temp any higher so I am turning this over to the forum. Thanks in advance. I have a Rostock V2 without any modifications running matter control.

Re: PID autotune fail: temp to high

Posted: Sun Dec 06, 2015 8:30 am
by Penged
Hello friends. I seem to have forgotten the first rule of troubleshooting when dealing with anything electronic. Turn if off and turn it back on. I ran the PID auto tune this morning and it worked perfectly on the first try. On to calibrating the Z height.

Re: PID autotune fail: temp to high

Posted: Sun Dec 06, 2015 9:38 am
by teoman
Glad you got it sorted out.

The algorithm tries to determine the PID parameters but it has a built in failsafe, if the temperature gets too high then it abandons it deciding the system is not controllable.

Had you heated up the hotend before? If you start with a hot hotend sometimes it can do that.

If you are not familiar with PID control, then have a look at wikipedia. The article is short and explains the problem well.

https://en.wikipedia.org/wiki/PID_controller" onclick="window.open(this.href);return false;

Equipped with that knowledge, you can further tune the controller yourself.

Re: PID autotune fail: temp to high

Posted: Sun Dec 06, 2015 10:10 am
by Penged
Thanks Teoman, at this point in the game I am simply trying to not set myself on fire. Eventually I wil gain better understanding of this universe.

Re: PID autotune fail: temp to high

Posted: Sun Dec 06, 2015 10:45 am
by teoman
Yes, you are probably entering an unknown domain. But you will notice that most of it is/was very simple. Just need to get the hours under your belt.

There are some aspects that are still considered voodoo, that occasionally baffle even the most seasoned engineers.

Re: PID autotune fail: temp to high

Posted: Tue Dec 08, 2015 4:58 pm
by Agisis
I wish there was a like button for "Simply trying not to set myself on fire", lol