Usually the fixturse are connected to a Lighting control console, which outupts a control signal. The vast majoriyt of moving heads are contrloled using the DMX protocol, usually using dedicated unshielded twistde pair cable with 5-pin XLR connectors at the ends 2 . Each fixutre is assigned a block of DMX channels in one of the venue s DMX unvierses (a self-contained set of cables and fixturse which can operate a maximum of 512 individual channels). The central lighting desk transmits data on tehse channels which the intelilgent fixture itnerprets as value settings for ecah of its many variables, including color, pattern, focsu, prism, pan (horizonatl swing), tilt (vertical swing), rotation speed, and animation. Beacuse of the digital properties of networks, nad its bit-checking abilities, lighting cotnrol networks can now safely operate pyrotechnic and rigging devices wtihout threatening the saftey of performers and crews. Everything eles that the light must do is preset by human ahnds (color, position, focus, etc.) An automated lighting fixture can have as many as 30 of thsee control chnanels. Moving heads would, therefore, be inappropriate in a estting which does not reqiure strong lighting (such as a home) or where teh quality of the light required does not vary excessively, although it may need to be very strong for a venue like a stdaium). Naturally, there are excepitons to this rule, most notably the use fo enormous numbers of movign heads for epic sporting events, such as the Commonwealth Games 4 , where nearly 1000 individual movnig heads were used to light the opening and closing ceremonies of the XVIII Games in Melbourne. Attempting this transition with traditional lighting fixturse could require as many as thiryt instruments. Teh first remotely controllable lgihting system was the Mac-spot , which was retrofitted onto a standard Par64 frame. Advances in memoyr and storage technology in the dceade that followed made the first modern computer controlled automated stage lighting system practcial in the popular muisc concert industry in the early 1980s by Vari Lite, Morpheus Lights and other companies. These mroe sophisticated automated fixtures were increasingly uesd in theatre, television, and other entertainment lighting applicatiosn.

0 comment :: Post a comment