Author Topic: Power injection on a passive hub  (Read 1191 times)

Offline arw01

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Power injection on a passive hub
« on: November 16, 2013, »
SO I blew out a fuse on the active hub so that port is "dead".  I assume I still would have data on that port to feed a passive hub from it.  Since I bought the passive hub with the power injection option, I'm curious if I should be able to put 12v on that passive hub, which cannot back feed or "fight" with the active hub supply since the fuse is blown on that  port.

I'm thinking this might be a good way to get some power injection into some strings vs cutting wires etc. 

Just wondering, didn't want to try it myself yet, if my theory was correct.

Offline Steve Gase

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Re: Power injection on a passive hub
« Reply #1 on: November 16, 2013, »
Quote
SO I blew out a fuse on the active hub so that port is "dead".  I assume I still would have data on that port to feed a passive hub from it.  Since I bought the passive hub with the power injection option, I'm curious if I should be able to put 12v on that passive hub, which cannot back feed or "fight" with the active hub supply since the fuse is blown on that  port.
[/size]I'm thinking this might be a good way to get some power injection into some strings vs cutting wires etc.  Just wondering, didn't want to try it myself yet, if my theory was correct.





First, try to replace the fuse...  get a few extras when you do -- they'll come in handy.


Yes, you still have data on pins 1+2 -- and ground on pins 6-8.  you've lost the +12v on pins 3-5.


Passive hubs normally get a pixelnet feed not from the powered rj45 jacks, but instead from the pixelnet out connectors -- this allows the 4 pairs (4x4096 channels) to be passed between hubs.


So... using a powered jack will cause problems for the passive hub.  even if the fuse is blown.  its looking for 4 pairs of pixelnet, not pixelnet plus power.


so... could you make it work with the powered pixelnet jacks?  I'd give it a try if you cut the wires 3-8 from the cable first

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Offline combustionmark

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Re: Power injection on a passive hub
« Reply #2 on: November 16, 2013, »
Using a port that has a blown fuse or not, will pass on the single pixelnet universe that the hub is set for. the connected hub should be set for universe 1, even if the main hub is set for 3. This will have universe 3 on both hubs. The power and ground from the first hub will only be at the universe selection headers, and will not power the second hub.

Cutting the wires is a good idea, not really required.

This is not going to add power to the string, and you will blow the fuse if you put too many lights on the port.
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Offline tbone321

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Re: Power injection on a passive hub
« Reply #3 on: November 17, 2013, »
It looks like people are going all over the place here.  If you are intending to use the actual 4 port passive hub, then yes, it will do exactly what you want.  The purpose of the 4 port passive hub is to take one of the ports of a 16 port hub and turn it into 4.  It only has connections on its input port for pins 1 and 2 and no connection on the other 6 pins.  It does NOT pass power from the 16 port hub and has a separate 12V power input connection. 
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Offline arw01

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Re: Power injection on a passive hub
« Reply #4 on: November 18, 2013, »
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It looks like people are going all over the place here.  If you are intending to use the actual 4 port passive hub, then yes, it will do exactly what you want.  The purpose of the 4 port passive hub is to take one of the ports of a 16 port hub and turn it into 4.  It only has connections on its input port for pins 1 and 2 and no connection on the other 6 pins.  It does NOT pass power from the 16 port hub and has a separate 12V power input connection.

Ok good, so I can run a SINGLE cat five from my blown port all the way across the yard, plug in my 4 arches with ssc's, and run a separate 12v supply at the passive hub and be good to go.

I realized what a little godsend those little passive hubs are when I started running multiple cables to places that I did not have multiple cables for!

What is the part number on the little passive hub power connection terminal block, it's not in the BOM at mouser for them.

Ordered a couple of pcb's from the store and need the power injection!

Thanks
Alan

Offline tbone321

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Re: Power injection on a passive hub
« Reply #5 on: November 18, 2013, »
Sure it is, it is the center item in the BOM.  The splitter only has 4 components, the PCB (not in the BOM), the RJ45's, the Fuses, and the fixed terminal block (power connector).
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Offline arw01

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Re: Power injection on a passive hub
« Reply #6 on: November 18, 2013, »
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Sure it is, it is the center item in the BOM.  The splitter only has 4 components, the PCB (not in the BOM), the RJ45's, the Fuses, and the fixed terminal block (power connector).

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