Lighting

Lighting Bars
Tech: *

All of the lights in stoic are powered through sockets mounted on the three lighting bars in the studio ceiling. These sockets are compliant to the latest safety standards so it's almost impossible to kill yourself on the rig. To connect a light, first lift the plastic cap on the socket. Then gently push the plug in a little bit. You will notice that the bar moves sideways when you do this. This is due to the lack of cross-bars which is in turn due to the poor nature of the 'real' (i.e. above the tiles) studio ceiling. So when you push the plug home you should hold onto the other side of the bar to stop it moving.

The sockets are numbered starting from the back of the room on the left-hand side looking towards IC Radio. So the left-most bar is sockets 1-12. then again starting from the IC Radio end the second bar is sockets 13-24 and the third 25-36.

Most of the lights are also physically hung from the bars using a lighting clamp. For obvious safety reasons the clamp should run under the bracket on the light and be bolted in firmly. A wing-bolt secures this to the bar. You should also always use a safety wire or chain in case the clamp falls off or fails. Safety wires are short lengths of wound steel wire with clips on either end. This is looped through the bracket on the light itself and over the lighting bar before being clipped back onto itself (see pictures). Safety chains are the same sort of thing but are chains as opposed to wire lengths. It is against the latest safety standards to use chains as the links can fail after many drops but sometimes we have to make do with them.
       
The image on the left shows a light correctly set up with a safety wire; the image on the right shows a light set up with a safety chain.

Dimmer Rack
The sockets in the bars are cabled back to the dimmer rack in the control room. This is the large creme-coloured unit near the video rack.
The dimmer rack powers all of the lights, from a dedicated three-phase mains supply which is cabled directly into it. The switch for this is on the right of the rack facing into the cool room. This should always be left on in order to avoid damage to the transformers and electronics of the rack due to repeated power surges. The dimmer rack is controlled from the lighting desk via DMX which is a signal protocol run along a single line to the control room.

Dimmer rack open to show modules

Each socket is cabled back to a single channel in the dimmer. The hardware for each channel is contained in the modules inside the rack. Each module contains two channels, so the total capacity of the dimmer is 72 channels. On the front of each of the modules is a power light, a signal light to show if the channel is active, and a breaker switch which acts as a fuse. There is also a control panel in the centre of the rack, which allows you to do very basic set-up and directly control the light brightness for debugging.
Under normal circumstances you won't need to go anywhere near the rack.
Important safety note: the power is run to the modules inside the rack via large, uninsulated copper plates. Don't even think about running the dimmer with modules out as this is obviously dangerous since the plates are live at 240V, at around 16A.
Oddities of Wiring - there are several important things to note about how this system got wired. As already stated, each module controls two channels. So channels 1 and 2 are on the top module, 3 and 4 on the second and so on. Unfortunately the contractor who wired it didn't know this and so wired one channel to each of the modules. This means that each studio lighting socket is on an odd-numbered DMX channel and the even-numbered channels do not connect to anything.
Also the connections to studio sockets 7 and 8 were installed the wrong way round.
However, these anomalies are corrected at the lighting desk using DMX soft-patch, described later.

The Lighting Desk
The system is controlled from a Zero88 Frog theatre lighting desk installed in the control room. This has its own power supply and is connected to the dimmer rack via DMX run on a CAT5 cable to the dimmer rack. This is connected to the 5-pin XLR socket in the sound furniture.
For information on how to use the desk, consult the STOIC Frog Operation Manual.
The first thing you will notice is that while we have 36 lighting channels, the desk only appears to have 24! The desk actually has 48, but you must put it into 'Wide' mode (using the button marked 'Wide' near the grand master slider) in order to address all of them. When in Wide mode, bus A (the orange-coloured sliders) controls channels 1-24 and bus B (green sliders) controls channels 25-48. There is a button to switch buses, this causes the desk to remember the values for each of the channels and then allow you to adjust values on the other bus (see the operation manual for more information)
DMX Soft-Patch - The channel numbers on the desk correspond directly to the socket numbers in the studio. All of the dimmer rack oddities noted above are compensated for using DMX soft-patch. This simply means relating the DMX channel numbers (on the dimmer rack) to the desk channel numbers. To change this, you must enter super-user mode on the desk (press FIXME...????.... what the hell is it??) and then go to DMX soft-patch in the menu. This gives you a table of the desk channel numbers and DMX channel numbers. Navigate using the UP and DOWN buttons (or cursor keys if you're using a keyboard) and use + and - to change the DMX channel (or type the number if you're on a keyboard).
You shouldn't need to change this unless you change the hard-wiring of the dimmer rack.