LSC Lighting e24V3 - Manual (Page 37)

e24 Dimming System
Operator Manual V2.2
LSC Lighting Systems (Aust) Pty. Ltd Page 33
10 DMX512 EXPLAINED
DMX512/1990-A is the industry standard for the
transmission of digital control signals between
lighting equipment. It utilises just a single pair of
wires on which is transmitted the level
information for the control of up to 512 DMX
slots (addresses or channels).
The information for each slot is sent
sequentially. The level of slot 1 is transmitted,
then the level of slot 2, then 3, etc. up to a
maximum of 512 slots. This stream of data
containing the levels for all 512 DMX slots is
repeated a minimum (generally) of 44 times per
second. This provides sufficient updates of
channel information for smooth fade transitions.
As the DMX512-A 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, the e24V3 dimmer
has a “DMX Patch” menu that allows you to
patch (connect) each DMX slot (address) from
your lighting controller to a e24V3 dimmer
channel number or to multiple dimmer channel
numbers.
When good quality data cables are used,
DMX512 cable runs may be up to 1,000 metres
in length. When several DMX feeds are required
(to feed different locations), DMX512 splitters
must be used. These provides multiple isolated
DMX512 feeds.
The e24V3 provides a “DMX Thru” output
allowing you to loop the DMX signal from one
e24V3 to the next. The last e24V3 in the chain
must have the “DMX Terminate switch” set to
TERM to terminate the line.
Note: Do not use unscreened microphone or
low speed data cables for DMX. This can cause
problems in the DMX network. Make sure the
cable conforms to the EIA485 cable
requirements by providing the following
specifications:
• Low capacitance
• One or more twisted pairs
• Foil and braid shielded
• Impedance of 85 -150 Ohms, nominally 120
Ohms
• 22AWG gauge for continuous lengths over
300 metres
The following diagrams illustrate a simple setup
utilising DMX512.
10.1 Typical DMX Installation
In the following example, the DMX output signal
from the lighting control desk is fed to the DMX
connector of the first e24V3 dimmer. The DMX
cable is then looped to the following e24V3
dimmers. The order of the daisy chaining is not
important as each e24V3 dimmer channel can
be patched to any DMX slot number. The end of
the DMX line is terminated to prevent the signal
reflecting back up the line and causing possible
errors.
e24
DMX
Slots
61-72 e24
DMX
Slots
49-60 e24
DMX
Slots
25-48 e24
DMX
Slots
1-24
Lighting
Controller
Termination
Switch set
to TERM DMX
Cable