Elation Professional DMX 101 - Manual (Page 17)

www.elationlighting.com 17
4.3 Data
DMX 512 data is transmitted at 250 kiloHertz (kHz), meaning that 250,000 1’s and 0’s (at a maximum) can be
sent each second. Each bit is measured in 4 microsecond (µs) intervals. In order for the receiving device to
correctly interpret the data, it must be sent in a particular sequence. A single transmission (DMX Packet)
includes synchronizing elements and channel data for up to 512 channels (Figure 8).
Figure 8
The following table describes each element of the DMX Packet, including its line state, size and duration. An
idle DMX line will have a continuous HI (1) line state.
Table 2: DMX Packet
NOTE: At a minimum, a fully loaded DMX Packet (data for all 512 channels) will be around 5700 bits in
size. This means about 44 DMX Packets can be sent each second.
WARNING: DMX 512 has no error prevention, and is prohibited from use in life-safety applications such
as pyrotechnics or set/rigging motion control.
Element Description State Size Duration
Break The Break resets the line,
signaling a new DMX Packet. LO (0) 22-250
kbits
88 µs - 1 sec
Mark After
Break
(MAB) The MAB signals the receiver to
begin reading data. HI (1) 2-250 kbits 8 µs - 1 sec
Start Code
(SC) The SC is identical in size to
channel data, but always 0 in
value. Mixed 11 bits 44 µs
Mark Time
Between
Frames
(MTBF) The MTBF is used to space out
individual data bytes. HI (1) 0-250 kbits Up to 1 sec
Channel Data
(CD) The CD carries the 8-bit DMX
Value for each channel, plus one
start and two stop bits. Mixed 11 bits 44 µs
Mark Time
Between
Packets
(MTBP) The MTBP is used to space out
entire DMX Packets. HI (1) 0-250 kbits Up to 1 sec
%5($. 0$% 6& 07%) &' 07%3 07%) &'
«
07%) &'
&KDQQHO &KDQQHO &KDQQHO
'0;3DFNHW
4