RGB, DMX, LOR, Cat cable and power injection

[beeiilll]

My appologies if this has been discussed before.
I posted this over on teh Australian Lighting Forum but thought that since there is so much interest in RGB, I would also post on this forum as well.
When using Cat 5 cable for hookup with the various RGB pixel nodes and strings and using power injection along the line is there any standard that most folks in the DIY section have adopted for a pin out to use.
I understand that pins 1 and 2 are the DMX signal lines and it appears that Dave from Holiday Coro makes his cables up so that the remaining 6 wires in a Cat 5 cable are used for the power injection by using the 3 solid colors twisted together as either + or - and the other 3 striped pairs twisted together as the other side (- or +).
Is this a fairly constant way to do the cat 5 cable for most folks or is there another way?
Just curious as the DMX signal also has a ground on most cables that I have seen so far, then I "assume" that most folks don't worry about using the ground line? I know that the -Ve signal is considered common for this is a non isolated DMX signal enviroment so the non use of the ground is not a big deal.
Or am I missing something here (which is entirely possible since I have spent the last week reading and studying this stuff and feel like my head is overloaded about now - LOL) or is this true?
OR do you not use all 6 wires in a cat cable for power and 'reserve" say one pair for ground or some other function that I am missing?
So can one of you nice folks steer me in the direction of a reasonable answer or is this something that really has no set definition of yet?
I just hate to build a bunch of things and then find out that everybody else uses some other standard. Especially if the folks who are designing some of the newer devices are using the RJ-45 jacks into things with power injection figured for certain pins on the jacks.
Thanks.

[edvas69]

Personally im not a big fan of power over ethernet, i like to keep them seperate. ethernet cable is officially rated at 1 amp per core so if your using a 5 metre strip of 12vdc 30 LED/M strip then you will require 6 cores, so yes that leaves 2 cores and no ground. this is where is can be a hit and miss thing, it will work for many not having the ground but then ive seen others where it wont work without a ground.

The other issue is that a lot of people use solid core CAT5 due to being cheap, this in itself is problamatic as our installations are only temporay and the CAT5 cable can easily break a core and then become overloaded especially if this is a return common core, then this can heat up and melt the insulation then putting 12vdc or whatever voltage into the data line and causing damage.

Another potential issue is mixing the cores around and accidently injecting power into the data line and causing damage as you are finding that there are not any decent standards that are followed within the hobby.

For me its not much more cost to buy cheap 4 core security cable which is rated at 4.4 amps and use that for your power and keep the CAT5 seperate. But then thats only my opinion. many others do it with power over ethernet and have no issues.

[Dr. Jones]

This is the Entertainment standard

http://www.dfd.com/t45.html

LOR uses the 2 wires that are not used with DMX- pins 4&5

Mixing DIY POE with this standard could result in possible damage

[beeiilll]

edvas69 wrote:

Personally im not a big fan of power over ethernet, i like to keep them seperate. ethernet cable is officially rated at 1 amp per core so if your using a 5 metre strip of 12vdc 30 LED/M strip then you will require 6 cores, so yes that leaves 2 cores and no ground. this is where is can be a hit and miss thing, it will work for many not having the ground but then ive seen others where it wont work without a ground.

The other issue is that a lot of people use solid core CAT5 due to being cheap, this in itself is problamatic as our installations are only temporay and the CAT5 cable can easily break a core and then become overloaded especially if this is a return common core, then this can heat up and melt the insulation then putting 12vdc or whatever voltage into the data line and causing damage.

Another potential issue is mixing the cores around and accidently injecting power into the data line and causing damage as you are finding that there are not any decent standards that are followed within the hobby.

For me its not much more cost to buy cheap 4 core security cable which is rated at 4.4 amps and use that for your power and keep the CAT5 seperate. But then thats only my opinion. many others do it with power over ethernet and have no issues.

Thank You Eddy

This is the answer that I was actually expecting to see (as well as somewhat hoping to see) from a person of "reasonable responsiblity, intelligence, and experience" in this hobby.

I was pretty sure that there was no standard for it but I did have a doubt after seeing the Aus listing showing the DMX connector listings for T-568, P-DMX, LOR, and JEC/wjohn:
http://auschristmaslighting.com/wiki/Connector_Pinouts#RJ45

which made me question as to whether an actual standard had been developed for this.

I actually agree with you on NOT using the Cat cable for power and data and am planning on going with seperate cabling myself as well.
I just figured that it does not hurt to ask when you have any doubts about something.
I am still in the planning stages for my incorporation of RGB into my display and wanted to "get the facts" on some things to make my set up plans.

While I can see where the use of the cat cable for things like the Holiday Coro stars and such is a nice simple way to hook them together, my 40+ years of electrical experience also tells me that it "just doesn't feel right" to do it. The problem with Cat cable with the solid core plus it being too small a guage just seem to glare out as a warning to me as "a problem waiting to happen".
While it can be done and be done safely as long as one takes the care to watch it closely and take the precautions, it can also be a hazard for those less experienced with electricity.
I was glad to see someone with the "credibility" in this hobby say so as well.

I also can not see where it will ever be a reasonable thing to do at this point. I can see where there will come to light a need to incorporate another connector into the mix of things possibly later on for this but there is already plenty of ways around the problem without any extra parts.
It doesn't take much to make a power supply in an encloser with multiple outputs for 5V, 12v, 24V, or whatever extra power that your display items may require or even to take a small supply and make some leads off it to run short distances to controllers, strips, nodes, whatever with better safety and cable management in mind.

While this is a "hobby" and people have the right to do as they please, it does behove people who understand the underlying principles of things to speak out and bring things to light for those who are not as knowledgeable especially in light of the number of people who are jumping into this in the last year or so. I see so many who have no knowledge of electricity getting into this field and there is a need to show them the hazards as well as the fun side of things in my opinion.

No one wants to be told that something is dangerous but is is way too easy to fail to "see the forest for the trees" with things and is becoming more so with the increasingly rapid developement of technology.

Also with the advancements in ethernet, LOR, DIY, E1.31, and other things on the horizon, I see the upcoming problems when someone plugs one of these POE "style" cables into a SansDevice board or an LOR board and lets out the magic smoke. That could be a costly error and a very easy thing to do if you happen to have a person or kid helping you set up your display and they inadvertently connect a cable wrong.

Perhaps it is time to take a look at this practice and make a standard up for "Christmas Lighting Power Distribution" for smaller scale devices out in the yard?
Maybe call it "Dedicated Electrical Auxiliary Devices" or DEAD for short? That might get their attention?
Reallky not a thing to make humor out of but you get my drift I'm sure.

I have no problem with people making up their own electrical items, but we need to remember that while WE understand this, not all the folks who are wanting to make a display are as knowledgeable nor will understand. They depend on the folks who do this to help them make it happen for their displays.

Bill

[Steven]

beeiilll wrote:

Just curious as the DMX signal also has a ground on most cables that I have seen so far, then I "assume" that most folks don't worry about using the ground line? I know that the -Ve signal is considered common for this is a non isolated DMX signal enviroment so the non use of the ground is not a big deal.

The 4-wire DMX equipment that you can buy from SeasonalEntertainment.com and HolidayCoro.com use the negative power wire as the DMX ground.

This probably works because most 12v power supplies and the source of the DMX signal often use the same ground. On the other hand, if you were to use an ungrounded power supply, like a wall-wart, that would result in the DMX signal being ungrounded.

[texascop]

The display was so much easier to manage when it was just LOR based. This year I am adding DMX. That looks like the way this hobby is heading. With any system integration you have to have system management. That requires labeling, diagrams, planning, all sorts of documentation. So regardless of what direction you go, you had better document it well or you are going to fry a lot of stuff. I have no problem with POE if it is used within it's limitations. We have over 400 wireless access points running POE. But, it has to be managed properly or you will have issues.

[Timon]

beeiilll wrote:

edvas69 wrote:
This is the answer that I was actually expecting to see (as well as somewhat hoping to see) from a person of "reasonable responsiblity, intelligence, and experience" in this hobby.

I was pretty sure that there was no standard for it but I did have a doubt after seeing the Aus listing showing the DMX connector listings for T-568, P-DMX, LOR, and JEC/wjohn:
http://auschristmaslighting.com/wiki/Connector_Pinouts#RJ45

which made me question as to whether an actual standard had been developed for this.
Bill

If your going to run Power over DMX the only way I feel it's reasonably safe is to follow the same basic standard that PoE does. The P-DMX standard is the only one that does that. Even if you were to plug a Ethernet cable into it you'd likely not fry anything. Same with mixing up LOR and P-DMX. The other standards including Hollyday Coro's, sorry David, I can't support as I think they're just too risky.

I think that P-DMX can work out quite well especially if we start using the chip sets for both ends that PoE uses and build them into our own devices. That will give us up to the 40W or so that you can do using just two pairs keeping each pair to 1/2 or less. This would require sending 48 to 57V but using the chip sets it totally safe. Trying to get into the higher area would require all 4 pairs and since DMX is not transformer coupled as Ethernet is that leaves the 4 pair option out.

IMHO
John

[edvas69]

Timon i would also suggest that if people do use POE that they use stranded cable and not solid cores.
As what i have stated before that in this hobby there are too many different POE configurations to make this option a good one for the avererage user within this hobby. If POE standards had been followed from the beginning and all the devices used followed these same standards with the correct protections then this could have been a good option, but unfortunatly it is not and is very fractured

[Timon]

Eddy,

You don't have the same ID over here:)

I agree that one should not use solid for interconnects as you going to end up have cable failures if you move them much.

As far as standards IMHO the only one that makes sense is the P-DMX one. There are really only three being use right now and that's RJ's, Davids and P-DMX. I really don't see the other one on the list as being a "Standard". J1sys is using the same P-DMX standard for his pixel extenders. I think that RPM as talked about using the same standard. So I think that's pointing us in the direction of P-DMX especially if we use it for both pixel extenders and P-DMX.

Remember we had the same problem when the first PoE came out but that got sorted out over time.

IMHO

John

[edvas69]

Ive always been a supporter of following standards, thats why im a big supporter of DMX and E1.31 because anyone can pick up a spec sheet and design something that can happily intergrate into a system now and into the future, the same is with POE, there is a known standard out there and if everyone was on the same page then that would allow for much less confusion and help future proof peoples displays. POE has its place but people must understand the current risks and that POE and POE are not the same thing from different vendors/designers.

For you who has a decent level of experience and knowledge going down the POE path will be little risk as you understand the differences and how to manage a POE network and would make a good choice for what your wanting to do.

The main thing im getting at here is that POE can be a good choice if you understand the different types out there and what to use so you dont get unstuck

[rstately]

Thanks Eddy,
for the 'AusChristmasLighting 101 manual'.
I made a donation, but I also wanted to say Thanks!

[edvas69]

rstately wrote:

Thanks Eddy,
for the 'AusChristmasLighting 101 manual'.
I made a donation, but I also wanted to say Thanks!

Thanks very much its appreciated and helps run the forum and to continue to provide easy to understand information on aspects of this hobby. Im glad you found it to be a help to you.

[Steven]

edvas69 wrote:

the same is with POE, there is a known standard out there and if everyone was on the same page then that would allow for much less confusion and help future proof peoples displays.

If you're referring to IEEE 802.3af-200, it seems to require Ethernet (10BaseT, 100BaseT, or 1000BaseT), and the fact that Ethernet pairs use transformers, as opposed to RS-485, which is a 3-wire standard that uses a common (ground) pin.

Thus, I don't think that standard would apply to RS-485 networks like LOR or DMX.

Although you could certainly use PoE on an E1.31 Ethernet network.

[Timon]

If you look at the standard there are two basic ways that power can be sent down the pairs.

1. Over a data pair using the center tap of the two transformers.

2. Over the two unused pairs.

In the case of gigabit it's always over a data pair since all 4 pairs are used for data.

For P-DMX we can only use pairs 4,5 and 7,8 since the data pairs are not transformer coupled. We can still use the PoE chips which would be better than blindly sending 48V down the line.

[Steven]

Timon wrote:

We can still use the PoE chips which would be better than blindly sending 48V down the line.

Now I understand! Yes, that sounds like a good idea (today).

If I understand my history correctly, the PoE standard is from 2003, but LOR was established before 2002. More importantly, when LOR was introduced, Cat5 cable was much more expensive than it is today, so they designed the network to work with telephone (4-conductor) cable. This meant pairs 1,2 and 7,8 were not available.

If LOR were introduced today, it would probably require Cat5, and those now-silly RJ-14 connectors wouldn't exist on the controllers.

[thebaddruid]

I use the ethernet method last year for my first display to control my DMX. I followed the instructions on Davis's HolidayCoro site to use with the 3 channel dmx controllers to control my few RGB fixtures. I just put together the RGB flood kit he has on his site and I am impressed with how bright and quick it took to put together. Would I use Ethernet for a huge dmx display, no but for the few I use it was pretty much plug and play.

[Tim Fischer]

thebaddruid wrote:

I use the ethernet method last year for my first display to control my DMX. I followed the instructions on Davis's HolidayCoro site to use with the 3 channel dmx controllers to control my few RGB fixtures. I just put together the RGB flood kit he has on his site and I am impressed with how bright and quick it took to put together. Would I use Ethernet for a huge dmx display, no but for the few I use it was pretty much plug and play.

I also based my "North Poles" design on the holidaycoro corostar design. My 'standard' was orange pair DMX, all remaining solids DC+, and remaining stripes DC-.

Like was noted, you need to watch how much amperage you pull on Cat5, but it works great for small loads (I injected the power in the 'middle' of my 9-pole run, so it's really a 5- and 4-pole run electrically. I also have a second 5-pole run injected from one end)

[dmoore]

Tim Fischer wrote:

thebaddruid wrote:

I use the ethernet method last year for my first display to control my DMX. I followed the instructions on Davis's HolidayCoro site to use with the 3 channel dmx controllers to control my few RGB fixtures. I just put together the RGB flood kit he has on his site and I am impressed with how bright and quick it took to put together. Would I use Ethernet for a huge dmx display, no but for the few I use it was pretty much plug and play.

I also based my "North Poles" design on the holidaycoro corostar design. My 'standard' was orange pair DMX, all remaining solids DC+, and remaining stripes DC-.

Like was noted, you need to watch how much amperage you pull on Cat5, but it works great for small loads (I injected the power in the 'middle' of my 9-pole run, so it's really a 5- and 4-pole run electrically. I also have a second 5-pole run injected from one end)

We've added a how-to video that shows how you can build a power injector using a standard power supply:

http://www.holidaycoro.com/kb_results.asp?ID=65


The start of the video also explains a bit about how power injection over CAT5 works.

[Steven]

dmoore wrote:

We've added a how-to video that shows how you can build a power injector using a standard power supply:

I've got a gripe:

Everybody seems to forget that DMX (and all RS-485 networks) are 3-wire networks, not 2-wire. They all have D+, D-, and ground. Ofter you can "get away with" not using the ground, because the devices may use another common ground, such as the power supply negative, or if the ground floats, the RS-485 chips themselves can cause this float to stabilize at a usable level.

But sometimes a missing ground can cause "weird" problems, especially in larger networks.

If we use proper cabling standards, the ground is always present.
In LOR networks, pin 6 is ground.
In DMX with XLR, pin 1 is ground.
In DMX over RJ-45, pin 7 is ground.

To maintain good DMX wiring practices, it is a good idea to maintain ground. Thus, when we build a XLR to RJ45 adapter, pins 1,2, and 7 should be used. (When using a 5-pin XLR connector, pins 3, 6, and 8 should also be used.

When we blend power and DMX on a Cat5 cable, pin 7 should be connected from the DMX source, and it should be used for ground, not +12v.

[dmoore]

Steven wrote:

dmoore wrote:

We've added a how-to video that shows how you can build a power injector using a standard power supply:

I've got a gripe:

Everybody seems to forget that DMX (and all RS-485 networks) are 3-wire networks, not 2-wire. They all have D+, D-, and ground. Ofter you can "get away with" not using the ground, because the devices may use another common ground, such as the power supply negative, or if the ground floats, the RS-485 chips themselves can cause this float to stabilize at a usable level.

But sometimes a missing ground can cause "weird" problems, especially in larger networks.

I agree on a technical basis and there is lots of history about the need for a ground in a differential RS-485 network in the industrial world. RS-485 is pretty forgiving though and works amazing well even with interference, lack of termination (LOR doesn’t terminate their lines) and lots of weird wiring configurations. Here is a real-world video showing lots of 3 channel DMX controllers over a CAT5 line with tons of splits and what it does and doesn’t do to the signal – all without a ground and with multiple power injection points:

http://www.holidaycoro.com/kb_results.asp?ID=17

If I was building a factory using Modbus over RS-485, heck yea I’d do a ground. For Christmas lights, I’d personally rather use that wire for power carrying functions.