M906 and very large current value?



  • Due to some very fat fingers and not double checking, I accidentally sent

    M906 Z10200

    (instead of 1000!) and printed for awhile. What would that do? Executing M906 again shows that value has been set to Z10200 but what does that translate into when actually using the motor? Is it equivalent specifying the maximum possible current and, if so, is that 2.4A?

    Thanks!
    Chris


  • Moderator

    @crpalmer said in M906 and very large current value?:

    Is it equivalent specifying the maximum possible current and, if so, is that 2.4A?

    I would think so. 2.4 is the limit in software. I suppose there's also the chance that it would take the first 4 digits and drop the last, which would give you 1000 as it's only set in increments of 100ma. @dc42 would have to confirm or deny.


  • Moderator

    @crpalmer I've done this, too! Yes, it just sets it to the maximum current possible on the board. It my case it resulted in a very hot motor, which took about 45 minutes to cool down. Fortunately it was on a Duet 2 Wifi (2.4A max current), not a Duet 3 (4.5A), which would probably have got the motor hot enough to melt the motor coils and fuse the motor. It did smell quite a lot of hot grease/oil, though!

    If the motor still works, I'd imagine it's fine.

    Ian


  • administrators

    Confirmed, the current you pass in M906 gets limited to the maximum supported by the board/driver.



  • Thanks for the replies. That would definitely explain why my motor stopped working. I wanted to confirm I knew why I had just killed the motor!


  • Moderator

    Sorry to hear that.



  • @Phaedrux thanks, but not a huge deal. It was just a Creality motor and I've replaced it with a slightly better Tevo motor from the scrap pile and it works better than ever now!


Log in to reply