The difficulty was that, on a regular basis, the DMX512-based production lighting system would need to take control of aspects of the house lighting. This would enable the overall visual effect to be controlled for a production. This presented a problem in that the DALI house lights were not compatible with the DMX512 controller.
Artistic Licence was brought in to provide a solution. Testament to the diversity of Artistic's technology range, this was achieved through a combination of standard products. First, a Rail-DMX-DALI unit enabled the output of the DMX controller to be translated into DALI commands that would be understood by the house lighting fixtures. The 64 short addresses corresponding to one DALI circuit were controlled by DMX channels 1-64. The Rail-DALI-DMX also supported the 16 group addresses required by the client. The DALI bus power supply was provided by another of Artistic's products, a Rail-PSU-D4.
The system also required a means to switch the DALI fixture circuit between the Delmatic system (house lights) and the Rail-DMX-DALI (production lighting). This was achieved using a Rail-Switch II product, which is a DMX controlled relay with 6 channels. All the relays in the Rail-Switch II were programmed to respond to channel 512 on the lighting desk. The overall solution enabled one universe of DMX to control all the DALI fixtures and also switch the control source.
Moreover, the installation was designed to ensure that the lights could not inadvertently become orphaned from either control system. In the event of a loss of DMX512 data or power, the 'data-loss mode' of the Rail-Switch II ensures that control is automatically switched back to the Delmatic system. This achieves the desired result of making the house lighting system the default controller when the production lighting desk is turned off or disconnected.
(Jim Evans)
