Single Power Source Problems

  • Hi,
    i try to connect the UniPi together with the Raspberry Pi 3 on Singe Power Source,
    Jumper JP1 mounted. The UniPi hangs on an Meanwell DR -15 -5 .
    Connecting the Power on does not powering on the RPi 3, nothing happens.

    If i unmount JP1 and connect an extra Micro USB Cable to the Meanwell DR-15-5,
    it work's.

    Is Single Power Mode not availiable anymore ?

    best regards

  • administrators

    Hello. Of course the single supply mode is still available. The only thing that I think of is the cable between UniPi and RPi but all cables are checked before shipment... Do you have a chance to connect at least the 5v and gnd from UniPi to RPi pins?

  • Hi Thomas,

    today i received 1 more UniPi+Raspi 3. It show's the same effect.
    Is it right, that there is only 1 cable between the 2 unit's, only the
    flat cable ?
    Should on the Raspi 3 be an LED on, if i connect power to the
    UniPi ?

    Which one are the 5V and GND pin's ? I am more the software man ...

    best regards,

  • administrators

    Hello, yep the one cable is everything you need. I will post a photo tomorrow that shows how it should be connected...

    Update: See the picture, it should be connected like that. 0_1476077237312_20161010_071735.jpg

  • Hi Tomas,

    that's exactly as i connected the cable. That seem's to be ok, as everything else
    (setting/resetting inputs and outputs) does work if i connected the power to
    the pi over the mini-USB port.

    Could you give me the Pins, where the 5V and GND should lie on ?

    best regards,

  • administrators

    The pinout of the first 2*13 pins is the same as on the RPi...

    Do you have a proper 5V power supply with the 2.1mm plug? If you connect your power supply to UniPi try measuring 5V on the power connector...

  • The 2.1mm plug is from you and is connected to the DR -15 -5, so it should run,
    but i don't have an extra power supply with the 2.1mm plug.
    I measured the voltage between ping 2-6 and 4-6. There is always 0V with and
    without JP1 mounted or not. So i think the problem lies on the Unipi, not the cable.

    Does it run on your side with Unipi and Raspi3 on single power source ?

    best regards,

  • administrators

    Powering UniPi from RPi is not recommended because the power supply on RPi is not designed for such big loads.

    Could you post serial number of your UniPi? FA55...

    Well if the DR-15-5 is OK, than check that you did not switched the cables to it (the red one is to +, black gooes to -).

    Also try to measure the voltage on the pinout of UniPi (or at least after the power connector) without the cable and RPi connected...

  • I measured the voltage on the pinout of UniPI without the cable,
    that's what i've done.
    Only the UniPI is connected to the power, i want to avoid the
    dual sourced power.
    The cables to the DR-15-5 are also ok.

    Do you have the same effect ?

    best regards,

  • administrators

    This is the first time I came across this issue.. Could you post some pictures of the setup and the serial number of the UniPi?

    If the RPi is not powered, than most probably the rest of the UniPi will not be powered also (relays, analog inputs + outputs, 1Wire,...).

  • i will send you the serial number's and some pictures later as i am not locally.

    Just to be sure, that i do not make a fault:

    • I connected the RasPI to the UniPI only with the flat cable
    • Only the UniPI is connected to the 5V Power
    • JP1 is unmounted
      Is that right ?

    best regards,

  • administrators

    Everything except the last step is correct. The JP1 must be mounted :)

    It should be unmounted ONLY if you want to have separate power supply for UniPi and for RPi.

  • JP1 has been mounted, sorry was faulty information.
    But finaly i found the problem: 5V GND was not connected
    to the UniPI power plug, only on the mini USB.
    Thank's for you help.

    best regards

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