The DMX protocol for controlling lighting technology has its roots in stage and event technology, but it can also be used in home automation. We show you how to control DMX devices with the Revolution Pi module.
In principle, digital multiplex (DMX) technology lets you control all DMX devices through a simple and robust bus. DMX uses the RS-485 specification (i.e., asynchronous serial transfer) for data transmission. The signal is transmitted over two lines simultaneously with inverted voltage levels (±5V).
This type of data transfer is resistant to external interference signals and theoretically allows line lengths of up to 1,200 meters. However, the data transmission rate decreases with increasing line length. Up to a distance of 10 meters, a maximum data rate of 10Mbps can be achieved over RS-485.
DMX works with a data rate of 250Kbps by default; a DMX network is built of strings. One string can contain up to 32 DMX receivers. More receivers require the use of a repeater to extend the network. Network branches are implemented with special splitters. Extremely robust, three-pole XLR (Cannon) connectors are used to connect all DMX devices, which is ideally suited for stage use.
Use Express-Checkout link below to read the full article (PDF).