Is it bad to send movement commands if motor disconnected?



  • I'm messing around with a slicer and sometimes I get the settings wrong and it retracts filament for a tool that is configured, but for which no extruder motor is connected.

    Will it hurt the stepper drivers in any way to send movement commands when the corresponding motor is not connected?


  • administrators

    It won't harm the drivers. The latest 2.02RC firmware is likely to warn you that the motor is disconnected.



  • Great thanks!



  • Not what you asked... but...

    Just a reminder to NEVER plug or unplug when powered, whether the driver thinks it is moving or not.

    "Hot" plug/unplug often kills driver chips.



  • Because of the wire getting caught on something during a print, the extruder motor wiring got disconnected. The extruder (driver) still works, so I'm just wondering what the probability is of the disconnection causing problems and if its a bigger problem if there is a lot of current versus less than an amp.

    Is it possible to safeguard against damage when a motor is accidentally disconnected, and if so, is that implemented on the Duet3?


  • administrators

    @jml said in Is it bad to send movement commands if motor disconnected?:

    Because of the wire getting caught on something during a print, the extruder motor wiring got disconnected. The extruder (driver) still works, so I'm just wondering what the probability is of the disconnection causing problems and if its a bigger problem if there is a lot of current versus less than an amp.

    Is it possible to safeguard against damage when a motor is accidentally disconnected, and if so, is that implemented on the Duet3?

    There are various levels of safeguarding that can be done. The best ones would add substantial cost to the Duet and require the board to be made larger. So we use a lower level, which is still fairly effective. See https://www.youtube.com/watch?v=uyWolKFzb-A.


 

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