Dimmer Control - Behringer EUROLIGHT LC2412 User Manual

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EUROLIGHT LC2412 User Manual

8. Dimmer Control

Dimmerpack
DMX512 output
Analog
output
0-10 V
0-10 V
switch
box
Mirror ball
Fig. 8.1: Standard wiring in combination with a dimmer (analog and/or digital control)
8.1 Analog control
In addition to the modern DMX512 interface, you can control your EUROLIGHT
LC2412's dimmers using the conventional analog outputs (ANALOG OUT (57) ,
0 - 10 V DC). However, this lets you control only twelve dimmer channels plus two
special channels (only "0 Volts" or "10 Volts").
◊
Whenever possible, use a multicore cable to connect your LC2412 to the
dimmer rack, and apportion the cable to individual dimmer packs only
once the cable reaches the rack.
8.1.1 Controlling analog dimmers via DMX512
What at first seems like an error is in reality a very useful feature: By using a
so-called demultiplexers (demux), you can convert digital commands into analog
and therefore control your analog dimmer packs.
The advantage of such a configuration is apparent: you can address the
demultiplexer freely, that is, it can for example begin with channel 12 and
therefore convert control commands from console channels 13 - 24 into analog
signals (DMX channel 0 is controlled one-to-one by console channel 1 and so on,
hence the numbering offset). Furthermore, you need only short multicores for
analog control, since you can arrange the demultiplexer near the dimmers and
send control commands via a single DMX line.
DMX512 input
LC2412 rear
Analog input
Tape/Send output
PRO MIXER VMX200
Fog machine
(with 0-10 V interface)
8.2 Digital control via DMX512
8.2.1 Digital control features
The EUROLIGHT LC2412 features a modern digital interface according to the
DMX512 Digital Data Transmission Standard For Dimmers And Controllers, that was
established in April 1990 by the USITT Engineering Commission (United States
Institute for Theatre Technology, Inc.). Since virtually all modern equipment uses
this standard (even if it is done with partially different plug-in connectors), your
EUROLIGHT LC2412 is therefore extremely flexible in how it can be implemented.
A big advantage of digital control is its enourmously simplified cabling, since you
only need one single cable for transmitting control data. This sets the DMX
system apart from its analog conterparts, which need an extra control cable for
each individual channel. Another big advantage is made possible by the freely
addressable receivers, which is done by menas of software. You can therefore
save yourself from having to painstakingly lay cables each time you wish to
assign a particular dimmer to a different channel. Additional information on this
subject can be found in chapter 8.2.2.
Interface format (EIA-485)
The DMX512 standard uses the RS485 interface standard for data transmission,
well-known for its impunity to interferrence. The data are serially transmitted in
the asynchron fashion at a transmission rate of 250 kBit/s, successively for each of
the connected dimmers (up to 512 channels). The more dimmers are connected,
the longer the time interval until the next command on this channel.
◊
It is advisable to limit the number of deployed channels in order to
ensure a maximum refresh rate. Therefore, do not use more channels
than you actually need.
In combination with the DMX512 standard, you can run up to 32 loads on a single
sender (LC2412). One load responds to one DMX512/RS485 receiver, for example,
the way it is implemented in a dimmer pack.
If you wish to run more than 32 loads, we recommend using level translaters
and/or signal splitters.
8.2.2 Assigning DMX channels (Softpatch)
Softpatch means: you can assign up to three freely selectable DMX channels to a
console channel.
◊
Each of the DMX channels can be assigned to only one fader.
Otherwise, contradicting commands would be given with various
fader settings.
To make the capabilities of the DMX512 as well as the capabilities of the LC2412
transparent, we have to draw a clear distinction between three different kinds
of channels:
Console channels
The channels of your LC2412 (= 24+2 channels) are 26 routes through which you can
send commands. This in no way means that you can only control 24 lighting elements.
Dimmer channels (Dimmer Loops)
Dimmer packs represent the power section of a light control system, comparable
to power amplifiers of a PA installation in the audio field. Each dimmer channel
is assigned to one DMX channel, that is, it can receive commands from only one
channel. For example, if a dimmer loop can handle a maximum power rating of
2.3 kW, you can connect several lamps, spotlights and similar (e.g. 4 x 500 W).