Power Injection

[davron12]

I've seen a lot of mention about "if you go over the 128/80 node limit you'll need to inject power" but haven't seen any mention of anyone actually doing it. Mega trees would be an ideal situation, since all the strings are close together, to inject power and cut down on the cost of having an SSC for each string. A disadvantage would be if you have one pixel acting up, that could mess up all the pixels after it, but you could save a few hundred dollars depending on the size of your tree.

How exactly would you inject power? You would need to join the data (green) from the end of one string to the beginning of the next. But what about power and ground? If you're using the same power supply, I assume you'd want to join both the end of the first string's power (red) and beginning of the second string's power with the injected power together with the injected power line, and do the same for the ground (blue) lines. What about if you have a different power supply? You'd still need to join the grounds together so that the data line would work, but would you join the power (reds) or leave the end of the first string's power alone and only join the power to the beginning of the second? Since we're dealing with 12vdc power supplies, I would think you could join the reds together too. I'm not sure if this is safe or not.

Lastly, if we did the above, any idea of how many nodes you could connect together?

Has anyone tried anything like this?

[dearvbguru]

I've seen a lot of mention about "if you go over the 128/80 node limit you'll need to inject power" but haven't seen any mention of anyone actually doing it. Mega trees would be an ideal situation, since all the strings are close together, to inject power and cut down on the cost of having an SSC for each string. A disadvantage would be if you have one pixel acting up, that could mess up all the pixels after it, but you could save a few hundred dollars depending on the size of your tree.

How exactly would you inject power? You would need to join the data (green) from the end of one string to the beginning of the next. But what about power and ground? If you're using the same power supply, I assume you'd want to join both the end of the first string's power (red) and beginning of the second string's power with the injected power together with the injected power line, and do the same for the ground (blue) lines. What about if you have a different power supply? You'd still need to join the grounds together so that the data line would work, but would you join the power (reds) or leave the end of the first string's power alone and only join the power to the beginning of the second? Since we're dealing with 12vdc power supplies, I would think you could join the reds together too. I'm not sure if this is safe or not.

Lastly, if we did the above, any idea of how many nodes you could connect together?

Has anyone tried anything like this?

Per RJ's documentation and videos, a single smart string controller will only control 128 nodes max.  If you put more on the string then it will only control the first 128 nodes and the others will be dark so it wont do you any good.  This limit is set in the Smart String Config Utility.

Steve

[Steve Gase]

For DMX power-over-cat5 non-RJ stuff, there is a different discussion to be had -- usually outside of this forum.

For RJ's equipment, power-injection is offered through active and passive hubs...  if you are reaching your power capacity, then add more hubs to introduce additional power supplies to spread your strings. 

[rm357]

RJ hard coded the 128 node limit and put fuses on the hubs to protect the hardware. Those wires and traces can only take so much current, and if there is something miswired or shorted, the damage that can be done is easily repaired.

If you bypass the fuse or inject power incorrectly, you can do a lot more damage...

For more advanced DIYers, I believe the fast nodes we use are capable of having 1024 nodes on a string with up to a 30Hz refresh rate. You will need to write your own firmware and inject power every 256 nodes - the power and ground can go either way along the string, but the pixel data can only go one way.... There will be little to no support available for this configuration through this board.

RM

[davron12]

Thanks. I think I got too use to setting up smart strings in LSP along with people talking about injecting power to go longer than 128, that I forgot there's a 128 limit in the ss config utility. Doh!