Lighting Networks 101

1
Lighting Networks 101
2
DMX

• Digital Multiplex Protocol
• or
• ANSI E1.11 2004
• USITT DMX512-A
• Asynchronous Serial Data Transmission Standard
  for Controlling Lighting Equipment and
  Accessories

3
Proper DMX Layout
Daisy Chain the signal path
Console

Fixture or dimmer
Fixture or dimmer
Fixture or dimmer
4
DMX Troubleshooting
T or Y connections change the cable impedance
causing reflection

Fixture or dimmer
Console
5
DMX Mixed Layout
Opto-splitter/Repeater
Console

Merger
Console
Each DMX leg out of a repeater is its own
electrical entity Repeaters can be daisy-chained
6
DMX Troubleshooting (2)?
Signal path must be terminated with 120 ohm
resistor
Console
Terminator switch or plug on final fixture

Fixture or dimmer
Fixture or dimmer
Fixture or dimmer
Failure to terminate causes signal reflection
back up the cable and intermittent problems
7
DMX Cable

• Low capacitance required to maintain wave form
• Belden 9842, 9729, 9829
• ProPlex, Showplex
• Cat5, Cat5e, Cat6
• Not microphone cable
• What they say about barb wire isnt true

8
Wave Form
Proper square/digital wave form

Sawtooth wave form likely caused by capacitance
in the cable or slew-rating in the transceiver
Wave form overlay (typically caused by
reflection)? Multiple overlays are possible
9
DMX Data Packet
High
Slot 1 (lvl0)? also 44uS
Start Code 44uS
Slot 2 (lvl0)?
1 start bit (low)? 2 stop bits (high)?
Mark-after-break 8uS
Break 88uS
Idle time can follow stop bits
10
DMX Data Frame
Line Idle - high
2 Stop Bits - high
1 0 0 1 1 0 1 0
8 Data Bits high or low
1 Start bit - low
Single Data Frame 11 bits altogether 44uS
transmission time
11
RDM

• Remote Device Management
• or
• ANSI E1.20 - 2006
• RDM
• Remote Device Management
• Over DMX512-A Networks

12
Why RDM?

• Because DMX isn't enough anymore
• Too much gear
• Too many universes
• Too much paperwork
• Too many places for things to go wrong
• Not easy to fix things on the fly

13
How RDM Works

• Does not make legacy DMX-only gear obsolete
• Uses a packet structure, like DMX
• RDM messages are interleaved or inserted between
  regular DMX packets
• DMX does not need to be present for RDM messages
  to be sent
• Requires all devices be transmitters as well as
  receivers

14
RDM Packet Structure
Start Code
Hex CC indicates RDM Packet
Sub-Start Code
Hex 01 basically for future use
Message Length
Number of slots used by message
Destination UID
UID of intended recipient
Not sure why only one controller allowed
Source UID
Transaction
Used to match query and response
Port ID/Response Type
Identifies controller's sending port and
responder's type of message
Message Count
Incremented by responder tells controller
number of queued msgs

Sub-device
IDs device within responder ie dimmer within the
rack
Message Data
Payload! At last!
Checksum
16-bit checksum of all above fields
15
RDM Message Block
Command Class
Get, Set or Discovery
Parameter ID (PID)?
i.e. Network Mgmt, Status, Sensors, DMX512
Set-up, others, or manufacturer specific
Parameter Data Length
Number of slots used by next part of message (can
be zero)? - responder needs to know when check
sum begins
Parameter Data
Format depends on the PID
16
New Rules for System Design

• No more than 4 in-line devices between a
  responder and the controller
• In-line devices include opto-splitters, mergers,
  repeaters, anything that reprocesses the signal
• In-line devices must be bi-directional
• Timing changes to DMX E1.11
• Break time extended to 132uS
• Each in-line device to reduce break by 22uS

17
Legacy Equipment

• DMX distribution gear developed prior to 2000
  will likely need to be replaced
• no provision for bi-directional signal
• end gear will depend on manufacturer
• as purchasers you should be demanding
  support for older gear
• DMX-over-Ethernet likely will be okay
• currently no programming consoles with RDM

18
RDM and Pathway

• Support for firmware upload over RDM
• DMX/RDM over Ethernet via Pathport
• In-line Devices
• DMX Repeater Pro
• Bi-directional opto-splitter
• Can also act as a controller
• eDIN 1009 RDM opto-splitter
• Responder Devices
• EDIN 1003 DMX to Contact Output
• eDIN 1004 DMX-to-Analog
• eDIN 1006 Analog-to-DMX
• eDIN 1008 DMX LED Driver

19
ACN

• ANSI E1.17 2006
• Architecture for Control Networks

20
Remaining Problems

• - sheer size of lighting installations (think
  LED) causing infrastructure problems
• - cost of wire and connectors for DMX/RDM
• - management tools not covered by RDM
• - multiple universe management
• - distribution management (merge, priority)?
• - everything still mapped to 512 channels
• - maybe the answer is... Ethernet?

21
Ethernet Advantages

• - Cheap wiring and distribution gear
• - available everywhere
• - 10 Mbit 40 universes at 250 baud
• (we get back to this one)?
• - flexibility of star wiring
• - cheap (did I mention cheap?)?

22
Proprietary Protocols(again)?

• Strand Shownet
• ETC Net1
• ETC Net2
• ArtNet
• Pathport
• ....and less often
• AVAB
• Compulite
• Enttec
• Colornet
• KiNet
• ... and none can talk to each other

23
DMX-over-Ethernet Advantages

• signal management
• - merging, splitting, priority switching
• unlimited outputs (dependent on network
  architecture)?
• up to 128 universes of input (typical 2008)?
• number of fully active universes varies from
  protocol to protocol but typically 12 - 15

24
Ethernet Limitations

• finicky installations
• sensitive to electrical interference
• not robust (compared to Belden/XLR)?
• 100m cable runs versus 500m for DMX

25
Enter ACN

• media agnostic use whatever cable you want
• intended as a generic language to control
  devices
• allows for plug and play

26
Alphabet Soup (1)?

• CID Component IDentifier
• DDL Device Description Language
• DMP Device Management Protocol
• SDT Session Data Transport
• RLP Root Layer Protocol
• Three letter acronyms not just for audio
  anymore

27
Alphabet Soup (2)?

• CID Component IDentifier
• - unique identifier for each device on
  system
• DDL Device Description Language
• - an XML file describing device properties
  and associated behaviours
• - controller can pick and choose what it
  wants depending on sophistication and need

28
Alphabet Soup (3)?

• DMP Device Management Protocol
• - how to get and set properties of the
  device
• SDT Session Data Transport
• - heart of ACN
• - allows efficient, reliable
  (error-checking) data transmission to one, a few
  or all devices on the network, depending on need
• - created specifically with the typically
  assymmetric lighting data flow in mind

29
ACN Overview

• - information not bound by 512 data slots
• - formatted or configured according to need
• - device reports native resolution
• - end devices can report abilities, parameters to
  the controller
• - no searching for libraries anymore
• - configuration using terms that make sense to
  the user
• - devices not limited to lighting equipment

30
How Will it Fit Together?

• - Ethernet backbone carrying ACN signals
• - some devices such as media servers, dimmer
  banks and LED drivers will sit natively on the
  network
• - gateway nodes will provide ACN-RDM control over
  configurable devices
• - gateway nodes will provide ACN-DMX control over
  legacy and 'dumb' gear

31
Whats on the shelf now?

• - DMX, obviously
• - RDM, increasingly
• - streaming ACN Ethernet protocol is available as
  Net3 (ETC), sACN (Pathway) and soon others (MA
  Lighting, Pharos)?
• - in the near term (5 years or less) sACN will
  replace the proprietary protocols
• - openACN group working on open source code
  modules (www.openacn.org)?

32
Ethernet Design Tips (1)?

• - structured wiring
• - IDC termination
• - TIA/EIA-568 certification
• - Cat5e vs Cat6
• -STP and conduit
• - observe cable lengths
• - max 90m for copper
• - copper versus fibre

33
Ethernet Design Tips (2)?

• - Power-over-Ethernet (802.3af)?
• - device classes and sufficient power
• - switches vs routers
• - current lack of Etherner protocol converters

34
Troubleshooting (1)?

• - managed vs unmanaged switches
• - bad things, maybe
• - broadcast storm control
• - IGMP packet sniffing
• - multicast filtering
• - spanning tree protocol

35
Troubleshooting (2)?

• - maximum traffic for 10Mb devices
• - 24 universes for broadcast protocols
• - traffic patterns
• - Ethernet component reliability issues
• - RJ45 vs Ethercon vs XLR
• - segregated traffic
• -VLANS
• - media converters