Wireless Artnet and sACN

[Cheeseweasel]

I'm trying to get my head around an upcoming show that will involve lighting a large crane with a variety of moving heads, architecturals and LED video panels.

 

Lighting/video control will be located in FOH, a distance away from the crane itself. The interesting part of the puzzle is that the current creative vision involves the crane endlessly slewing round throughout the performance, which rules out any sort of cabled connection. Power won't be a problem, as it will be delivered through a system of slip-rings built into the crane, but getting data across the gap won't be as simple.

 

We generally send sACN, Artnet and TitanNet, as well as various other network data for audio system control etc down VLANs on a gigabit ethernet connection, based around Luminex Gigacore switches. In an ideal world, I would like to send the gigabit trunk line wirelessly up to another Gigacore in the crane via a point-to-point link. The network will be fairly busy during the show, so the connection would need to be reliable and fast enough to be able to cope. The distance for the P2P link will be around 10 metres, and at 180 degrees rotation, will have the crane's main truss between the two transceivers.

 

I found this old topic on the subject, which contains no definitive or very satisfying answer:

https://www.blue-room.org.uk/index.php?showtopic=50868&st=15

 

I'm aware that running a cable is always preferable to even the most high-tech wireless alternative and the general advice is probably not to do it, but I wondered if anything had changed over the past seven years.

 

Towards the end of the linked topic, microwave links are mentioned. I have no experience with them but would be interested to know if a microwave-based solution might work.

 

Thanks in advance.

 

Tim

[gyro_gearloose]

Do you really need 100MB of data per second? Thats several hundred universes of DMX. Having a 'slower' wireless connection should be more achievable/reliable, and still give you tens of Megabytes per second of data.

[timmeh2]

Hi

 

Personally I'd go for distributed computing and stick your media servers on the crane along with whatever your equivalent system for DMX replay is (in the GrandMA world we use NSP and NDP) - that way you're just sending control rather than huge amounts of DMX and video down your pipes, which would be far more manageable.

 

Microwave links are point to point and fixed. If you have something that moves then it's a non-starter. They are also a single point of failure.

 

All the best

Timmeh

[operalx]

What about a rotary fibre optic joint? If you can mount in the centre of the slew ring.

 

https://www.bgbinnovation.com/optilinc/

http://www.trolexengineering.co.uk/fibre-optic-rotary-joints.html

Edited March 16, 2019 by operalx

[Cheeseweasel]

Do you really need 100MB of data per second? Thats several hundred universes of DMX. Having a 'slower' wireless connection should be more achievable/reliable, and still give you tens of Megabytes per second of data.

 

I certainly don't need the full gigabit bandwidth, but there is still a fair bit going on apart from the sACN, e.g. there is potential for multiple HD video streams to be sent over the network on a separate VLAN and I'd like an over-engineered solution with plenty of excess capacity. Point taken though - if it's more reliable to have a slower connection could you suggest some hardware?

 

Hi

 

Personally I'd go for distributed computing and stick your media servers on the crane along with whatever your equivalent system for DMX replay is (in the GrandMA world we use NSP and NDP) - that way you're just sending control rather than huge amounts of DMX and video down your pipes, which would be far more manageable.

 

Microwave links are point to point and fixed. If you have something that moves then it's a non-starter. They are also a single point of failure.

 

All the best

Timmeh

 

This is my other line of thinking. It will all depend on the available space on the crane structure, but sending TitanNet wirelessly to control a second console on the crane would seem like a good idea. I'll be meeting with Avolites in a couple of weeks anyway so I'll get a chance to pick their brains. It still leaves the issue of the various other data I need to get up to the crane though.

 

What about a rotary fibre optic joint? If you can mount in the centre of the slew ring.

 

https://www.bgbinnov...n.com/optilinc/

http://www.trolexeng...ary-joints.html

 

I like a lot. I would much rather have an answer to this problem that doesn't involve any wireless technology at all. They also seem to manufacture capacitively-coupled slip rings designed to pass ethernet up to 1000BASE-T, which could be ideal for me as I can mount a couple in the crane's power box with the rest of its slip rings. I'll give them a ring next week. https://www.bgbinnov...0Capacilinc.pdf

[Cheeseweasel]

After a bit more research, the slip ring idea seems by far the most technically elegant way to do this. A quick search for 'ethernet slip ring' turns up all sorts of products designed to pass multiple gigabit ethernet, low voltage power and HD-SDI lines across a rotating joint. It seems they are fairly commonplace in industrial robotics.

[timsabre]

But you would need to be able to place the device at the pivot point of the crane arm. This is unlikely to be possible as the crane's own power feed will already use that point.

[Cheeseweasel]

But you would need to be able to place the device at the pivot point of the crane arm. This is unlikely to be possible as the crane's own power feed will already use that point.

 

This won't be an issue. It's a large crane with a cabinet of 20 copper slip-rings of various sizes fed from a gear off the main slew. They won't all be needed for powering the crane's systems, so either some could be removed from the spindle and replaced with data slip rings, or the spindle could be extended fairly easily by one of our fabricators.

[xllx]

['ll be meeting with Avolites in a couple of weeks anyway

 

I did a job a couple of years ago at the London Eye, we had to get DMX to all 32 capsules, I'm pretty sure Avolites were involved in doing this, possibly in conjunction with Stage Electrics who are involved in most of the gigs there. Basically 32 DMX streams were sent wirelessly from one desk on the shore to 32 receivers in the capsules. I can't recall if it was 32 separate universes or not. Took some setup and fine tuning, but performed flawlessly on the night.

 

Edited to add:

Ah, just noticed that you also want to run video over your network - we did that with wireless video links form Presteigne Broadcast, but we weren't integrating the video and the lighting, it was just cameras sending form the capsules to the shore.

Edited March 17, 2019 by xllx

[Crash_Override]

I have used both the LumenRadio CRMX (https://lumenradio.com/product-category/entertainment-lighting/indoor/) and Wireless Solutions WDMX (http://wirelessdmx.com/products/blackbox-f-1-g5) and haven't had any issues with signal. I don't know about WDMX but Lumen has a outdoor version. Lumen is ok with sACN, haven't tried with WDMX but according to the spec. it will work. Depending on the universes you need.

[Cheeseweasel]

Just to give some closure to this old topic...

 

I ended up going down the Fibre-Optic Rotary Joint (FORJ) route, as suggested by OperaLX. We designed a mounting system for the FORJ and had a machinist modify part of the existing power slip-ring assembly to accommodate the FORJ on the end of the slip-ring stack.

 

I was keen for a way of sending the ISL (trunk line) between Luminex switches past the crane's slew, as we already own a bunch of Luminex kit which forms a backbone network with separate VLANs for ArtNet, TitanNet, audio system control and a few other bits and pieces. It was useful to be able to make all of these available on the crane. For safety reasons we also needed a reliable wired comms link between crane operators and everyone else on the ground, so I created a separate VLAN for Helixnet, with HXN base-stations at FOH and above the slew.

 

A couple of industrial network switches fitted with bi-directional SFP cards did the conversion between copper and fibre for sending through the FORJ. These use Wave-Division Multiplexing to send the Tx and Rx signals used in traditional fibre communications down a single piece of fibre at different wavelengths, meaning we were able to use a single-channel FORJ rather than a dual-channel model (which tend to have more complicated optics and cost a lot).

 

The system performed well all weekend without any noticeable dropouts, and has enough excess bandwidth to accommodate bigger and better things next year.

 

Thanks for everyone's input!

 

Cheers

Tim

 

 

[operalx]

I’m glad the suggestion was of use and your integration was successful.

[IainB]

I saw that the thread had a response and went through from the start and thought.....oooh that sounds like Acradia, then I saw Tims response LOVE what you guys do, its inspirational to a 'newbie' in this world

[Bryson]

I ended up going down the Fibre-Optic Rotary Joint (FORJ) route, as suggested by OperaLX. We designed a mounting system for the FORJ and had a machinist modify part of the existing power slip-ring assembly to accommodate the FORJ on the end of the slip-ring stack.

 

I was keen for a way of sending the ISL (trunk line) between Luminex switches past the crane's slew, as we already own a bunch of Luminex kit which forms a backbone network with separate VLANs for ArtNet, TitanNet, audio system control and a few other bits and pieces. It was useful to be able to make all of these available on the crane. For safety reasons we also needed a reliable wired comms link between crane operators and everyone else on the ground, so I created a separate VLAN for Helixnet, with HXN base-stations at FOH and above the slew.

 

A couple of industrial network switches fitted with bi-directional SFP cards did the conversion between copper and fibre for sending through the FORJ. These use Wave-Division Multiplexing to send the Tx and Rx signals used in traditional fibre communications down a single piece of fibre at different wavelengths, meaning we were able to use a single-channel FORJ rather than a dual-channel model (which tend to have more complicated optics and cost a lot).

 

The system performed well all weekend without any noticeable dropouts, and has enough excess bandwidth to accommodate bigger and better things next year.

 

I love this: I wonder if the client had even the slightest inkling of the depth of technology required to facilitate this. Nice work.