LSC Lighting NEXUS - Manual (Page 43)

NEXUS Specifications
Operator Manual V1.01
© 2011 LSC Lighting Systems (Aust) Pty. Ltd Page 37
9 Terminology
9.1 DMX 512
DMX512 is the industry standard for the transmission of digital control signals between
lighting equipment. It utilizes just a single pair of wires on which is transmitted the level
information for the control of up to 512 DMX slots. As the DMX512 signal contains the level
information for all slots, each piece of equipment needs to be able to read the level(s) of the
slots(s) that apply only to that piece of equipment. To enable this, each piece of DMX512
receiving equipment has an address that you can set. This address is set to the first slot
number to which the equipment is to respond.
The end of the DMX line is terminated (120 Ω) to prevent the signal reflecting back up the
line and causing possible errors.
9.2 DMX UNIVERSES
If more than 512 DMX slots are required, then more DMX outputs are used. The numbers
on each DMX output are always 1 to 512. To differentiate between each DMX output they
are called Universe1, Universe 2 etc. Each universe is carried on its own cable.
9.3 RDM
RDM stands for Remote Device Management. It is an “extension” to DMX. Since the
inception of DMX it has always been a ‘one way' control system. Data only ever flows in one
direction, from the lighting controller outwards to whatever it may be connected to. RDM
changes all that allowing the equipment to answer back!
RDM has been designed to work with existing DMX systems. It does this by interleaving its
messages with the regular DMX signal over the same wires. There is no need to change any
of your cables but because RDM messages now go in two directions, any in-line DMX
processing you have needs to be changed for new RDM hardware. This will most commonly
mean that DMX splitters and buffers will need to be upgraded to RDM capable devices.
9.4 ARTNET AND SACN
ArtNet and sACN are Ethernet protocols that transmit DMX over a LAN (Local Area
Network). Unlike a DMX cable that only carries 1 DMX universe, ArtNet or sACN supports
multiple DMX universes on the one cable.
9.4.1 Artnet
Artnet supports up to 256 universes. These are arranged in 16 sub-nets each containing 16
universes. 2 hexadecimal digits are used to specify the subnet / universe. Hexadecimal means
that each digit has 16 possibilities 0-9, A-F (unlike decimal that has only 10 possibilities, 0-
9). With these two digits you can have a maximum of 256 (16 x 16) different DMX universes
on the network.
Number Sub-Net Universe
0 0 0
2 0 2
3 0 3

10 0 A
11 0 B

16 1 0
17 1 1

200 C 8

255 F F