multiple power supplies with power injection

[wbartles]

Hi everyone!!  The holiday is near!

My issue is I can't seem to confirm a particular wiring procedure for my display setup.  I want to use a 5 volt power supply for my E6804 (it runs much cooler) but my pixels are 12 volts, so I am using a 12 volt PS to run them.  I've read several articles about tying grounds together of multiple PS's (for stable DATA) but separate the Positive line from the 2 PS's.  Do I also do that in my configuration, by tying the grounds only of the 5 volt AND 12 volt PS's together??

Thanks to anyone who can confirm this for me.  It's too close to the holidays to burn anything up!  LOL

[Gilrock]

Yes you want to tie the grounds together between those power supplies because they need to both agree on what "ground" is.  Without that one supply could define ground a couple volts higher than the other and then you get a higher voltage than you expected on the data line.  Definitely DO NOT connect the positive lines to together.

[Burrington]

You can NOT power 12 volt pixels with a 5 volt power supply. They will not light up, or will be very dim at best.

You can run multiple power supplies for different sections of the string by connecting the ground and data lines through the complete string, and connect the power wire for each section to its respective power supply.

If your single power supply has sufficient capacity, but the lights at the far end are dim, you can also run an additional 2 conductor wire from the power supply to the far end of the string, connecting both + and - all the way through. That saves a power supply and is cheaper and simpler than adding a second one.

It is not a good idea to connect multiple power supplies to the same power wire. Slight variations in voltage will cause uneven distribution of the load on each power supply and could overload one of them. Also, if one of them gets unplugged the entire load will be on one supply. Depending on the power supply, it could also become a load or even a short circuit for the power supply that is powered. So, always separate the power wire so the + side of the power supplies are not connected together through the string.

[wbartles]

Ok, so just to make sure....  I have power injection theoughout my whole display and all is good from that perspective, I just want to make absolutely sure that I can tie the grounds together between my 5 volt power supply and my 12 volt power supply.  This way the controller is running on 5 volts and all my pixels are running on 12 volts but 'everybody sees the same common ground. The reason I do this is because I have noticed that the controller runs cooler on 5 volts.

[RandyS]

The answer is yes.   

[wbartles]

Thanks to all.  I apologize for not explaining my question very well.

[Burrington]

Ok, so just to make sure....  I have power injection theoughout my whole display and all is good from that perspective, I just want to make absolutely sure that I can tie the grounds together between my 5 volt power supply and my 12 volt power supply.  This way the controller is running on 5 volts and all my pixels are running on 12 volts but 'everybody sees the same common ground. The reason I do this is because I have noticed that the controller runs cooler on 5 volts.

Sorry, I thought you meant you were trying to run your 12v nodes with a 5v supply. I agree with previous responses that YES, you CAN do what you described above.