Duet Ethernet - where to get +5V?



  • I'm trying to find a "good" location on the duet wifi/ethernet board to get a +5V source (that can be grounded to PS_ON via an SSR) when the duet is powered via USB (and I'd prefer not to splice the USB cable.) I have the EXT_5V_EN jumper removed and the INT_5V_EN jumper attached.

    My first thought was the +5V pin right next to the PS_ON pin, but then I read that "There is a Schottky diode between the USB 5V power input and the internal 5V rail, also between the external 5V power connector and the internal 5V rail. " That suggests that the 5V pin next to the PS_ON pin won't provide 5 volts (and it only "consumes" it.)

    The only other thing I can find is +5v from pin 1 of the expansion header. I hate to use that (because I intend to add a Duex board at some point.) I also see that the "EXT 5V EN" jumper has two pins, one labeled "5V_IN" and the other labeled "+5V." Would one of those provide the 5V I need and would it cause a problem for me if I used one and it grounded via PS_ON?

    In other words, I intend to attach pin 4 (DC GND) of a SSR-25DA to the PS_ON pin on the duet. What (on the duet) can I attach pin 3 (+3-32VDC) of the SSR to so that the m80/m81 commands turn on/off the relay?

    Thank you
    Gary



  • You can use the fan jumper (5v/Vin 3 pin one) +5v pin. But it runs from the 5v Reg on the board so it won't handle a lot of current 1-2A max? Don't quote me on that.



  • @DjDemonD:

    You can use the fan jumper (5v/Vin 3 pin one) +5v pin. But it runs from the 5v Reg on the board so it won't handle a lot of current 1-2A max? Don't quote me on that.

    I don't really need much current to drive a SSR, but will the 5v pin on that jumper be active when the duet is only powered from USB (and therefore not from the internal 5v regulator)?



  • I'm not sure, but why not get the power from the USB power source?



  • @DjDemonD:

    I'm not sure, but why not get the power from the USB power source?

    Because the USB power source is a simple micro USB "wall wart" that I'd rather not splice if 5V is readily available from the duet board.


  • administrators

    You can also get +5V from the Panel Due port. But as 3V is enough for SSRs, i suggest you use +3.3V from an endstop connector instead



  • Just out of interest David, does connecting a USB power source provide power to the 5v fan selector jumper pin if the ext 5v en jumper is set to external?


  • administrators

    @DjDemonD:

    Just out of interest David, does connecting a USB power source provide power to the 5v fan selector jumper pin if the ext 5v en jumper is set to external?

    Yes, although when using USB power the voltage is around 4.5V because of the diode between the USB socket and the +5V rail.


Locked
 

Looks like your connection to Duet3D was lost, please wait while we try to reconnect.