Duet Expansion Header Breakout


  • administrators

    Short note: we have produced a specialist breakout board for connecting external drivers that require a differential signal at 5V

    https://www.duet3d.com/Expansion_Breakout

    This is not needed for the majority of external drivers, any questions feel free to ask below!



  • Hi; I just ordered one of these for that exact purpose. Is there a hole pattern diagram for this somewhere? I'd like to cut a mount to my controller mount plate before it arrives.

    Thanks


  • administrators

    I have added a wiki page on this, thanks for the prompt:

    https://duet3d.com/wiki/Expansion_breakout_board#Dimensions

    The dimensions are shown in this image:

    And the source files are on github:

    https://github.com/T3P3/Duet/tree/master/Duet_Expansion/Expansion_Breakoutv1.0



  • Nice. Thank you!



  • I just got one of these. However, none of my leadshine drivers works with the board. I don't have a oscilloscope, so I can't test the step pulse, however, with a multimeter I found the voltage between e+ and e- is 3.3v with the driver is enable and -3.3v when the driver is disabled. Is this the expected behavior? I thought it should be 0v and 5v.


  • administrators

    Have you increased the step pulse width for your external drivers using the M569 command?

    The voltage reversal is intentional and helps the photodiode in the opto isolator turn off snappily.



  • @dc42:

    Have you increased the step pulse width for your external drivers using the M569 command?

    The voltage reversal is intentional and helps the photodiode in the opto isolator turn off snappily.

    Yes, I've been using the drivers (leadshine ES-D508 and EM503) with logic level converter with the same configuration. I brought the Expansion Header Breakout to get rid of the messy wrings. I've tried every single port on the Expansion Header Breakout, non of those works. another thing I've noticed is that my 7" paneldue start to flickering after I plug in the expansion header breakout and the drivers to it, the 5v voltage would change between 3.8v and 4.4v (this does not happen with the logic converters; unplugging paneldue does not help with the motors). I've tried to connect a driver back to the logic converter, it would work again.
    Also while I tried to diagnose the problem, I noticed while using external 5v 2A source with nothing connected to the board. The 5v pin on the expansion slot only provides 4.6v, while the voltage at the input pin is 4.996v, is this normal?


  • administrators

    External 5V power and USB 5V power are both fed through diodes, so it's normal for the voltage on the 5V rail to be a little low when using those 5V power sources.



  • I got the problem solved. My drivers are active high but I don't have the R1 parameter in M569. so it's default to active low. It's still strange that the drivers would work without the Expansion Header Breakout.


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