Heater Bed Fluctuation



  • Hi guys,

    I just retrofitted my Creality CR10 Pro with a duet 2 wifi and Im seeing very high fluctuation of my bed temp (using bang bang method). This only starts about an 30mins after starting a print and when I pause printing the line straightens out. Paused, I also wiggle some cables to see if it fluctuates but it doesnt seem to. Any ideas what the issue might be?

    Creality Temp Chart.JPG


  • Moderator

    Is the bed thermistor wiring running near any stepper motor wiring?

    I suggest you do a PID tuning of the bed and save the results. Bang bang is not recommended.

    https://duet3d.dozuki.com/Guide/Ender+3+Pro+and+Duet+Maestro+Guide+Part+4:+Calibration/40#s183



  • @jsera That temperature trace is showing temperature excursions of around 20 - 30 deg C in a matter of seconds which can only be a noisy signal. As @Phaedrux said, check the routing of the wiring. You haven't told us what temperature sensor you are using but it could be a faulty sensor. If it's a PT100, use 4 wire and/or screened cable.



  • Thanks for the tips guys, yes its right under a stepper and the more I notice, it fluctuates more when that axis moves. I havent seen what kind it is, but it has 2 white wires so Im thinking its the same as the hot end, 100k thermister.



  • So the cables were very close (y stepper and bed thermister). I separated them and shielded the stepper and now its a straight curve. No fluctuation anymore. Thanks for the help!


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