Power loss recovery



  • We have a rather large creatbot d600 printer we recently converted to a duet wifi. I'm in the process of trying to setup power loss recovery. The power provided to the duet comes off of a large bank of capacitors, but doesn't seem to detect the loss in voltage fast enough to save/move the head. Everything just stays powered on for a few seconds after you yank the plug, but the duet doesn't seem to realize until the capacitors run out of juice?

    The original board received a signal from a module that monitors loss of mains power. Does the duet have an input that can read this and take action on, or is the voltage dip the only way it can know if mains power has been lost?


  • administrators

    Can you confirm that you are using 24V power? What value have you set the power loss voltage threshold to in the M911 command?

    Currently the Duet power loss procedure can only be initiated by a drop in the measured voltage; but I am considering allowing a power loss signal from an endstop input to be taken into account.



  • Hi,

    Yeah it's using 24 volt power. Here is a photo of their module. The endstop input might work with this, although I'm not exactly sure how this implementation worked with their marlin which they refused to release the source code for.0_1551227547542_Photo-2019-02-25-17-53-21_3456.JPG


  • administrators

    If the output circuit of the PCB in that box is configured to provide ab active low output then it should be possible to connect it to an endstop input. If not, it would be possible to modify it to provide an active low output.

    What M911 parameters are you using? In particular, what power loss voltage threshold?

    What motor movements are you trying to do on power loss? If you have a capacitor bank then it should at least be possible to retract a little filament and lift the head a little.


 

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