Trouble with heater bed faulting



  • Hi Guys,
    I see others having trouble to get the heater of the bed to work properly.

    My issue is, I cannot complete the teaching cycle. The temp just keeps rising till it shuts down.

    I have a 220V heater bed, diam 300, driven by a SSR.

    When I start the auto tuning, I set the P to 0.3 and the max temp to 110.
    The temp starts to rise and never stops. Straight line on the graph.

    Do I need to set the bed at a different temp? I tried to set the bed at 100 and the max temp to 125. No difference.

    I will try again, but am not getting anywhere.



  • I was previously using 1.15beta3 without any issues, but since updating to 1.15c just now I am also getting bed faults.. typically after running IR calibration.


  • administrators

    Lykle, I went to the trouble of coding an error message that says exactly what needs to be done when the temperature limited is exceeded during tuning. Hint: when tuning a high-powered heater, you need a much lower P value than the default 0.5.

    Brian, you need to tune the bed heater, or at least adjust the heater model to account for the properties of your heater. See https://duet3d.com/wiki/Tuning_the_heater_temperature_control.



  • OK, good news, managed to tune my bed heater. Set the PWM to 0.2 and it managed to complete the tuning cycle.
    It turns out, one of my mistakes was adding too many statements. Once I removed the max temp it sailed through. (40 mins or so)

    Now it is stable as a rock.
    So for me, this problem is solved.


 

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