Dimming - DMX control

DMX512 is a serial protocol for controlling lighting technology such as dimmers and other special effects using a digital interface. The protocol has been maintained since 1998 by the Entertainment Services and Technology Association (ESTA). The multipoint connection topology creates a bus with one master and multiple controlled devices. The bus uses the RS-485 interface and is typically implemented through a 120 Ω two-wire line, and the slave stations form a so-called ring, and the last station has a terminating resistor connected. 

According to the DMX512 / 1998 standard, the standard XLR connector is 5 pins, a socket on the transmitter side and a plug on the receiver side. However, a 3-pin XLR connector is usually used.

The requirements for the DMX bus connection are electrically identical to the RS-485 bus:

1. Strict line connection without taps, taps, resp. branching into a star can be solved using active elements (hub).
2. The line must always be impedance terminated at both ends. E.g. on the master module side we will use the bus termination, which is available on the MR-01xx submodule (see the example in Fig. 1 for the MR-0106 submodule) and is activated by flying the surfaces on the submodule (for description see TXV 101 15 submodule documentation), the other end of the bus (the last controlled DMX device) is terminated with a resistance of approx. 120 Ω.
3. The bus must be run with a shielded cable (recommended cables for RS-485)  with twisted pair (data wires), the shield must be connected to pin 1 of the connector. The shield must not be connected to the metal connector cover!
4. Due to the real possibility of interference (power control of lighting, etc.), it is necessary to implement the installation correctly and follow all recommendations.

The DMX bus master can only be implemented in the basic Foxtrot module, using the MR-0105, MR-0106 or MR-0115 submodules. 

It works only on communication channels CH3 and / or CH4, where there is an RS-485 interface because only these channels allow transmission at a speed of 250 kBd.

Support for lighting control is available in the Mosaic environment in the form of ready-made function blocks.

The shield for the standard connector must be on pin number 1 (5-pin connector), it must not be connected to the metal cover of the connector.

DMX connector:

                                          5-Pin XLR Fork                                                        3-Pin XLR Fork