Lighting Ethernet

[Tom_Robbo26]

I have recently worked in a theatre, and I have noticed many ethernet ports around the theatre and have also noticed that this is a feature on the back of lighting desks. I noticed this on a GrandMA desk.

 

I was wondering what these are used for as I have no idea.

[dunk_1984]

Around the room there is a high possibility they are for the internal computer network. In Scarborough they have wall sockets and Wireless Access Points.

 

In sound and lighting kit it is so that they can be networked much like computers, they are then programmable etc via PC. This is also the case on things like XTA speaker distribution units/Sound management units, you can network them so as you can control via computer remotely as you can obviously use wireless in the network. So especially useful for delay tower/speaker tuning as you can actually go and sit/stand there with your laptop. Also these days you will see network sockets appearing in the backs of speakers, so as you can control them individually.

 

I think in essence Ethernet is taking over the job of people running round tweaking things as they are all controlled from a central computer.

[Jonny DMX]

The ethernet ports on the back of GrandMA desks is so that you can connect the desk to a network. From this network you can connect to other GrandMA desks so that you can have more than one desk and programmers working on the same show. You also use the network to connect the desk to NSPs to expand the DMX outputs of the desk. It is also possible to connect the GrandMA to a laptop or computer running MA lighting software so that you can pre program on the visuliser or to set up an auto save function when programming for example.

 

There are other lighting systems that run on networks, like artnet, that may benefit from a theatre that is well supplied with ethernet connections. Im not sure but I seem to think that fixtures like the DL.1 and .2 can run direct from a network connection. Also I have noticed that some Robe lights have started coming with an RJ45 connector on. I don't know if there is a function for this or not? it could be used for updating the software? or Robe could be trying to future proof their fixtures for when ACN finally becomes a standard!!!

 

Frankly I think it makes very good sense to equip a theatre with Ethernet connections, especially with so much more being connected via a network these days.

[tvi675]

The Ethernet port on the lighting desk is used to connect to devices such as Network Signal Processors (NSPs), remote nodes, ethernet to DMX converters, etc. As far as I'm aware, the (but sure I'll be corrected if I'm wrong!) the GrandMA does not output ArtNet or Pathport, which are two commonly used DMX over ethernet protocols but other desks, such as ours do. This allows you to just connect up your ethernet cable between front of house and the dimmer racks, and use an Ethernet to DMX converter to get DMX out at the other end. Particularly useful if you are running a large number of universes (say for an LED or video wall) as it can all go down one small cable rather than a multi core of larger ones.

 

Talking specifically about our MagicQ desks now, the ethernet port can also be used for remote file management so you can log into the console from your computer, move and copy show files, upgrade the software and personality libraries, etc. We also support remote control via the ethernet port and external windows over ethernet. The ethernet port can also be used to connect to media servers like ArKaos or Hippotizer and pull thumbnails and live previews of the output of the media server back to the console using the MSEx protocol, and also connect to various visualisers such as Capture or WYSIWYG.

 

Just a few uses of the ethernet port there

 

Matt

[Oovis]

As far as I'm aware, the (but sure I'll be corrected if I'm wrong!) the GrandMA does not output ArtNet or Pathport, which are two commonly used DMX over ethernet protocols but other desks, such as ours do.

Looking at the GrandMA OnPC software it seems to have configurations for both ArtNet and Pathport, and even seems to allow different protocols on each universe, though how that would work down one UTP cable escapes me at the moment...

[bruce]

To be pedantic, the sockets you see on the wall are RJ45 outlets with CAT5 or similar UTP cable behind them.. They may be running Ethernet, but they could just as easily be used for DMX, phones, comms circuits, audio links, etc etc... But don't assume that just because it's a RJ45, it must be ethernet...

[KindredHyperion]

I believe part of the reason for the trend towards DMX over Ethernet, particularly in larger venues, is the substantial difference in cost between CAT5 and DMX data cable. The possibility of transmitting several universes of DMX through one cable is also a bonus.

[mac.calder]

I think it is more the several universes through one cable (and the reduced footprint that one socket gives you) that are the main benefits. For example, my work has a minimum of 14 universes of DMX at any one time - most of that is solely for houselights/features lights/pannel lights/table spots in the ballrooms etc. Previously, before ArtNet, controlling houselights manually, or creating custom looks on the featurewalls involved running four universes of DMX to the desk and half an hour patching, compromising with splitters to mirror certain universes outputs for some rooms, and the results were patchy at best.

 

Now? Plug desk into ethernet port. Fire up PC and change the VLAN the port is on to the lighting network. Load show file.

[Cormac]

http://images-eu.amazon.com/images/P/1904031293.02.MZZZZZZZ.jpg

 

I've found wayne howells book on Ethernet in the lighting/entertainment industry very helpful and quite relevant to Lighting and DMX,worth a look if you are coming to terms with new forms of DMX distribution.

 

Regards Cormac

[Jonny DMX]

If you are genuinely interested in learning more about this subject area (which IMO is the cutting edge of control systems in the lighting industry at the moment) you could do worse than to read John Huntington's book Control Systems For Live Entertainment. The book is currently in its second edition but from what I hear he is in the middle of writing the third edition. (ISBN: 0-240-80348-5)

 

http://images-eu.amazon.com/images/P/0240803485.01.MZZZZZZZ.jpg

 

Jonny

[Tomo]

I wrote a really long and carefully-written explanation last night, but then my UPS ran out of batteries and shut the PC down...

 

Cat 5e is fast becoming the de-facto choice for installed data distribution in new builds and refits - it's cheap and there are loads of installers that know how to pull it.

 

In many venues, it's simply a tieline - there is an ESTA standard for DMX-over-Cat5, and there are many 'adapters' to put various data signals onto it (eg VGA, audio)

 

However, lighting-control-over-Ethernet networking is fast becoming popular, because it reduces the cables required - often to just one at the lighting console - and offers some features that never existed before.

 

There are several common protocols you'll see:

1) ETCNet2 - ETC's proprietary standard, licensed out to several other manufacturers (eg Arkaos, Capture Sweden, Pathway)

This has a limit of 32,767 control channels, or 64 universes, and provides a range of filtering, precedence and softpatching functions.

 

2) MA-Net - MA Lighting's proprietary standard, used primarily for data distribution to NSPs and backup consoles.

Again, 64 universes, but a different set of features and limitations.

 

3) ArtNet - Artistic Licence's free standard.

This has a theoretical limit of 255 universes. It also does not play nicely with other network services or scale very far due to the broadcast packets, but is perfectly good when it has a small private network to play on.

 

4) Streaming ACN (sACN) - a subset of the new ESTA ACN standard, designed to be scalable and simple to implement.

This has a theoretical limit of just over 64,000 universes, although even Gigabit ethernet can only cope with around 5000.

This has big advantages over ArtNet as it allows for priority, and also plays much nicer with other network services due to its multicast nature. It's also incredibly scalable.

 

ETC have released source code for anybody to download and play with sACN to speed implementation by other manufacturers - I expect the uptake to be very fast as it's a very easy protocol to implement.

 

The big disadvantage all these protocols have is the simple one of topology (how it's connected together).

DMX is great - it's a daisy chain, so you go from one end of the lighting bar/truss to the other, going into then out of each fixture.

If you ran Ethernet to all these, then you'd need one Cat 5 for each unit!

 

I see the future as being Ethernet distribution to the end of each bar or truss, and then DMX cables down the bar - anything that's relatively fixed (eg media servers) will get Ethernet straight into them so it can sit in a rack out of the way.

[Jonny DMX]

I see the future as being Ethernet distribution to the end of each bar or truss, and then DMX cables down the bar - anything that's relatively fixed (eg media servers) will get Ethernet straight into them so it can sit in a rack out of the way.

 

I completely agree with this. I know in theory one of the advantages of ACN (I have not heard of sACN before, so don't know how this differs) is that you could plug your whole system together via a star topology as you do with any computer network and turn the control desk on and simply 'find' the fixtures attached to the network. In theory you could then 'address' the fixtures from there and adjust pan and tilt info or even adjust fan speeds and have overhead indicators from the desk. However I too think that for the time being the transition period will be a single DMX universe per truss. I would expect the device to look very similar to an Avo truss mount DMX splitter or eDMX device. these would then be identified on the ACN compatible desk (I think the Jands Vista is) as a DMX universe, lets say "truss 1" which would then send DMX as normal.

 

I think that with ever more LED making its way onto shows eating up DMX universes ACN is needed more than ever! One problem that I can see with ACN is that DMX is a continuous stream of information and is time dependent so that all fixtures recieve all information at all times. However ACN is based on large open computer networks designed around delivering non-time-critical data, in the lighting world we need to be able to deliver the information in a predictable amount of time so that we don't have different fixtures reacting at a different time from the same cue!

 

Jonny

[Tom_Robbo26]

The big disadvantage all these protocols have is the simple one of topology (how it's connected together).

DMX is great - it's a daisy chain, so you go from one end of the lighting bar/truss to the other, going into then out of each fixture.

If you ran Ethernet to all these, then you'd need one Cat 5 for each unit!

 

I think im beginning to understand and I completely aggree with your vision of the future. But would there ever be a way invented for ethernet to be daisy chained from one fixture to another? As people have said in other replies to this topic some fixtures are now appearing on the market with ethernet ports built in.

 

Is this an impossibility with the protocools and conventions of ehternet or is there a chance it could ever happen?

 

Thanks Tom

[Tomo]

I think im beginning to understand and I completely aggree with your vision of the future. But would there ever be a way invented for ethernet to be daisy chained from one fixture to another?

Yes, there is already a way to do this - you need to fit a 3-port switch into the fixture itself.

Two ports are then exposed to the outside world, with the third connected internally to the fixture's control processor.

 

This does present a few challenges - adding a single Ethernet port is cheap, but reliable switch hardware and firmware isn't.

There's also some things about the internal routing tables, although a 3-port where one port is fixed probably makes that easier.

 

I'm not sure if there is a theoretical limit to the number of daisy-chained switches, but each switch does add a short delay of a few microseconds - and these add up!

[martinw]

The biggest issue with having an Ethernet switch built into fixtures is that if one fixture loses power, then all the other fixtures further down the chain will lose their data signal.

 

I don't think that Ethernet distribution directly to each fixture will be used widely used anytime soon, there's just no compelling reason for doing it. What I think will happen is that control systems will be based around an Ethernet backbone, probably using ACN streaming, which will slowly replace all the other protocols. This backbone will connect the consoles directly to the dimmers and will probably reach as far as the end of each lighting bar, at which point there will be a cheap ACN-DMX/RDM gateway, to which the fixtures will be connected. Many theatres are already setup this way, but I think it will become much more common in the near future.

 

Martin