In short, the DMX is a “language” essentially used to control lighting and special effects from a controller.In order to effectively control multiple lighting and effects, a language (also called a protocol) that works with any lighting equipment, regardless of the brand, will be needed. In the field of lighting, we use the DMX protocol, officially named USITT DMX512 / 1990. The DMX is lighting what MIDI is to music. There are several ways to control DMX lighting, but a controller is the tool of choice for most lighting technicians. This is because of the quality of its faders and buttons to which you can assign a function, which is then sent in DMX to the device of your choice (PAR projector, LED scanner or effect machine, for example).
The image on the right shows how to connect devices to a DMX controller. As you can see, DMX devices are connected in series. The dedicated inputs and outputs of each device will be used for this purpose.
2. How do DMX channels work?
Each function of a device has its own channel. Each channel is assigned a value from 0 to 255, allowing you to control the various parameters precisely through the faders and buttons of your DMX controller. This value can therefore correspond to all the parameters such as, for example, the intensity of the light (0 = off, 255 = maximum intensity) or the angle of rotation. It is also possible to “cut” a series of gobos into pieces. In this case, the values 0 to 29 will correspond to gobo 1, 30 to 49 to gobo 2 and so on until 255. Consult the user manual of your projector or light effect to discover the number of channels, their functions and the effect provided by the different values.
3. Why is it necessary to address DMX devices?
In order to control several DMX devices independently, it is necessary to perform a DMX addressing for each device, on the device itself. DMX addressing involves assigning each device to a number of channels. Most often, we address the devices behind each other. For example, if the first device has 8 channels, you address it in “1”, the second in “9” and so on until 512 (the maximum number of channels that can be sent by a DMX cable). Caution: When using a rudimentary DMX controller, it is possible that, by default, 16 channels are reserved for each device. In this case, it will be necessary to address the first device in “1”, the second in “17” and so on, this in order to simplify the piloting.
The most recent devices are addressed by using an LED display. Older models work with a DIP-switch assignment (also known as a binary switch). The DIP-switch is a set of switches each corresponding to a particular value. To address your device to the channel of your choice, activate the switches to be added to reach the desired number.
4. Can I use DMX software to manage my lights and effects?
Those who wish to have more control and flexibility – and have the time to delve into the subject – should consider the possibility of managing their lighting on a laptop or tablet via software. This allows you to program your different projectors and / or effects and control them live.
By combining the different functions of your devices, you can create ever more dynamic effects. The programming possibilities are almost endless. If you are the type to prefer to work with buttons and faders, know that it is possible to connect a MIDI controller to the USB port of your computer / tablet!
Since most people will need a certain amount of time to become fully familiar with the world of DMX software, we recommend that you only devote to it for shows and complex shows. See also question 5.
5. Or would it be better to opt for a physical DMX controller?
Whether you choose a physical (controller) or virtual (software, see question 4), working with DMX requires good planning. Of course, it also depends on the complexity of your controller and show.
For less complex shows, a simple DMX controller would be the most practical and affordable solution. However, do not forget to check how many DMX channels you need, so you do not end up with a controller that is not suited to your situation.
If you plan to organize complex shows with a lot of projectors and effect machines, we recommend that you contact us so we can help you make the right choice between a full lighting controller and DMX software.
6. What is the difference between a DMX cable and an XLR cable?
Each DMX-compatible device is equipped with DMX input and output. These are actually XLR connections comparable to those found on mixing consoles. The DMX connection can be done using 3-pin or 5-pin XLR cables ; the 5 pins being the industry standard, but less widespread in practice than the 3-pin version (see image on the left).
It is also possible to use XLR cables dedicated to DMX , which are a bit more expensive but much safer than XLR cords designed for the transmission of audio signals . Their 110 ohm impedance allows them to transmit a large number of signals at a time. Highly recommended when working with a lot of devices!
7. What are the alternatives to DMX?
First of all, be aware that many projectors, light shows and effect machines can be used independently . Thus, you can select a fixed color for your LED projector and a motion effect for your light show, or have your device react to music. In short, a perfect solution for small coffee-type configurations, for example. These settings are normally done via a small screen on the back of the unit.
Pkmarts.com: To control traditional lamps that do not have DMX or other advanced features – such as, for example, halogen PAR projectors – you can use a dimmer (“dimmer”). A power block (“dimmerpack”) 4 channels to adjust the intensity of up to 4 lamps. Using a switch pack is an even more rudimentary solution: this device simply turns on and off your various lights and effect machines.
If you’re looking for an even more basic solution, you can head to the 230-volt 19-inch switch panels . They are in fact standard power distributors (not controllable via DMX) equipped with an on / off button dedicated to each connected device. Of course, it is also possible to connect several devices on the same output to turn them on or off at the same time. These switchboards can easily be mounted in a flight case or a 19-inch rack.