Heater turned on unexpectedly



  • Not more than 5 minutes ago, my idle printer's hot end fan turned on, and I went over to check why. I was at the time not connected to the network that it's on, and at first the duet display showed both thermistors at room temperature, so I put my finger close and confirmed that the heater block was in fact hot. After doing this and looking down, the temperature now read ~150c and climbing. So I logged on to the Duet web control, and saw it at about 230c, with Active set to 0, and Standby set to 240c. I set standby to 0, and it peaked at 245c, before falling.

    I don't know what happened, but this is very concerning to me.

    I often leave my printers on, ableit inactive, when unattended, and the prospect that one of them might suddenly set themselves to heat up is dangerous for obvious reasons. I'll cease doing that for now, but I'd like to know if this is a known behaviour.

    Firmware version; 2.02(RTOS) (2018-12-24b1)
    Firmware Electronics: Duet WiFi 1.02 or later
    WiFi Server Version: 1.22
    Web Interface Version: 1.22.6



  • @MortarArt As you say, that behaviour is concerning. No doubt someone more knowledgeable than I will post a reply but in the meantime, you might do what I do and that is put G10 Pn R0 S0 (where n is tool number) in config.g, and your slicer end gcode, and any cancel.g macros. That will ensure that the active and standby temperatures are always set to zero other than when printing. It doesn't resolve your issue but it should help to mitigate it.



  • Good idea. It's possible there was some kind of power fault and the printer reset to that state. But normally standby is 0. The last job I did was in ABS, at 240c so that's where the standby temp came from.



  • Also, think about updating the firmware to the last stable RR2 release



  • @jay_s_uk yeah, I will do. But I'll wait until someone from Duet3D replies in case they want to run some tests to check things.


  • administrators

    @MortarArt said in Heater turned on unexpectedly:

    Good idea. It's possible there was some kind of power fault and the printer reset to that state. But normally standby is 0. The last job I did was in ABS, at 240c so that's where the standby temp came from.

    Unfortunately most slicers don't understand firmware that supports active/standby temperatures, so they use M104 or M109 to set temperatures, which sets both. If the slicer doesn't reset them with M104 S0 at the end, it will leave the temperatures set.



  • Yes, but what I don't understand is why the printer decided to turn on the heat to the standby temperature. It was completely idle.


  • Moderator

    @MortarArt From your initial description, you have a PanelDue connected? Could something have pressed the screen, just in the right place to turn on the heater to standby? It's quite sensitive.

    Ian



  • Maybe an insect? The room was otherwise still enough for me to hear the fan turn on.


  • Moderator

    @MortarArt Maybe interference? It's a tough one to diagnose, and as far as I know, no one else has reported anything similar.

    Ian


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