Lighting Circuits
The ease with which DMX can be installed means that its layout is often modified to suit new requirements. The diagram below is therefor likely to be out of date in detail but it includes some items of interest which will probably stay as they are. You can click the picture for a full size version.
DMX universes
The cables marked A and B are the two universes supplied by the Magic Q wing. Cable A controls everything except the house lights. Cable B is shown controlling the house lights and the follow spot but we no longer use the follow spot link.
DMX switch
The "DMX switch" in the lighting box is on the front wall near the dimmer packs:
It has four channels. Three of them (254, 255, 256) switch undimmed mains power to the IEC sockets on the box. Channel 257 controls a voltage free contact on the red and black terminals.
Channel 254 is used to switch undimmed power to the glitter ball and the four pin-spots that illuminate it. The other channels are currently unused.
DMX splitter
DMX has to be connected to the lights in a daisy chain. This is a problem when branches are needed but the item marked "DMX splitter" solves this. It is a mains powered unit which buffers and retransmits the signals on cables C, D and E.
Proc. Arch RGB controller
The item marked Proc arch RGB Controller located in the stage manager's area is for the 25 strips of LED lighting around the proscenium arch. Each of these strips has its own address and can be controlled individually. The power for the system is taken from the repurposed E2 socket.
House Lights
The "House lights" controller is located near the door at the bottom of the lighting box ladder. When the indicator LED on the cover is blue, the house lights can be turned on or off by the switches near the auditorium doors (the switches also show a blue LED). When the indictors are red, the house lights are DMX controlled and can be dimmed in three groups of four- left, right and front of the auditorium. In this state the switches near the door have no effect.
Very occasionally, due to circumstances we haven't yet understood, the DMX address of the controller changes from its expected value of 250. In this case it has to be manually reset see below.
4 way Dimmer Packs
The two "4-way Dimmer Packs" provide dimmed mains in the same way as Dimmer Pack 1 in the lighting box. They are used for the legacy lights mounted on the vertical poles either side of the stage where there is no fixed wiring from the main dimmer packs. They are limited to 5A per output so each output can only be used by any one of our legacy lights.
Dimmer pack circuits
The main dimmer packs in the lighting box, using DMX channels 1 to 42, provide controlled mains power for the legacy incandescent lights. The cabling for this is fixed, so each light is plugged into a particular socket, either directly or on an extension lead. The fixed socket locations are shown although the cabling to them is not.
Bar A has what look like 12 double sockets spread along its length but each socket of the pair is independent of the other and is duplicated in a position mirrored about the centre of the bar. The reason for this is that it is common to light an area on the stage with two lights spread apart but served by the same circuit. For example, circuit A1 is available for a light at each end of the bar with no further extension leads.
Sockets D5 and D7 at the back wall of the stage are no longer used as dimming circuits. Instead their corresponding plugs in the dimmer pack area are plugged into ordinary mains. This provides mains for the DMX controlled lights via local blocks of IEC sockets.
'Bar E' is not a lighting bar at all, just a pair of sockets in the Stage Manager's area. As with D5 and D6, E2 has been re purposed to provide undimmed mains from the lighting box.