Astralpool DMX Manuel D'installation Et D'entretien page 3

2. OPERATION
The modulator receives orders from the DMX controller (for example Astral DMX, 41329, or Astral DMX Pro, 41330 controllers) of
the system through the DMX bus, and operates on the projectors connected. While the DMX signal is not received from the
controllers, the projectors will remain off.
This modulator has been designed for use only with protocol DMX and the controllable elements via DMX of AstralPool.
3 channels can be controlled through the DMX modulator, corresponding to red, green and blue of all the projectors connected to this
DMX modulator. In this way, it is possible to achieve 256 different levels for each colour. By mixing these three colours, over 16
million colours can be obtained. Each modulator should be assigned an address that will determine the three channels it can control
(see Assignment of DMX address).
Assignment of DMX address
The modulator uses 3 DMX channels: red, green and blue, the display of the modulator shows the address corresponding to the red colour, the
following address corresponds to the green and the next one to the blue. If for example in the display we have the "009" this indicates that
through the channels 9, 10 and 11 we will control the red, green and blue colours.
The buttons + and – that are in the display are used to select the DMX address. Once the wished address is selected, its memorizing takes 3
seconds. After that, the modulator will already be totally operative.
Example:
DMX line termination
At the last terminal of the DMX line, the line termination should be activated. At the remaining terminals, the line termination should be
deactivated.
In DMX modulators, the line termination is activated connecting the connections 14 and 15 with a cable and connecting with another cable the
connections 16 and 17.
DMX communications bus
The DMX signal can be affected by electrical noise from other signals. It is recommended to install the DMX bus away from electric cables and
other interferences.
The maximum length of the DMX bus is around 100 m., although it varies depending on the conditions of each installation. In adverse
conditions, repeaters (splitters) (code 41645) should be installed in longer lengths or line branches.
The DMX signal is transmitted from equipment to equipment through a "daisy chain" type connection, where the equipment is connected in a
chain. The DMX cable with the original signal leaves the DMX controller and is sent to the first equipment of the DMX link. From the first
equipment, the signal goes to the next one and so on. The DMX line is terminated in the last equipment (see previous section). Different
equipment can be connected at any point of the line whatever the assigned address.
It is not possible to connect more than one DMX controller in the same DMX bus.
The cable used should be suitable for this type of signal: shielded, twisted pair with a nominal impedance of 120 ohms (80 - 150) and low
capacitance, with a minimum thickness equivalent to 24 AWG.
3. EXAMPLE OF A DMX SYSTEM
In a DMX system, there should be a controller and different types of terminals can be used.
A system with the following elements is given in the connection diagram below:
- DMX controller: Astral DMX (code 41329), including software and interface.
Terminals:
-
The Astral DMX interface is connected to all the DMX terminals of the installation through a DMX cable (code 41646) as shown in
the figure. All DMX terminals are connected in series using one single communications bus. The last DMX terminal of the line
should be configured to indicate that it is the last terminal of the communications bus.
Base address = 9
Red: Channel 9
Green : Channel 10
Blue : Channel 11
Base address = 12
Red : Channel 12
Green : Channel 13
Blue : Channel 14
2x DMX modulator (code 41107) with 2 projectors with PAR 56 lamp (code 41109)
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