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DMX 512 Chart www.americandj.com/pdffiles/DMXCHART.pdf

DMX 101           Barry Abrams 

DMX 512 is a standard protocol by means of which lighting, controllers and control desks can communicate with lighting equipment. It was designed to allow equipment from different companies to be used together easily.       Continue for more education....

Glossary of Stage and Lighting

DMX 512 is a standard protocol by means of which lighting, controllers and control desks can communicate with lighting equipment. It was designed to allow equipment from different companies to be used together easily.

DMX 512 is a standard protocol by means of which lighting, controllers and control desks can communicate with lighting equipment. It was designed to allow equipment from different companies to be used together easily.

Where did DMX come from?

The first dimmers/fixture functions were actually controlled by levers on the dimmers/fixtures themselves.  During a show, it could take several men to move these levers and someone else to coordinate them. This kind of control was quite cumbersome. Later, control wires were run from each dimmer/fixture function to a control console. If you had 300 dimmers/functions, you had to have three hundred control wires! To improve this, manufacturers started using digital signals sent down one control cable. At first each manufacturer used their own protocols, meaning that different manufacturer's equipment could not be combined. Finally, DMX 512 was adopted as the standard lighting control protocol.

DMX has 512 individual channels, which can be set to a level between 0 and 255. If a dimmer/function was addressed to be on channel 1, and the level of channel 1 was brought up to 255 (or 100%), the dimmer/function would be sending out full power. Therefore, a color/gobo or other functions are assigned a number from 0 to 255.

Example:

Channel 1 Gobo
0 = Blackout
10-20 = Gobo 1
20-30 = Gobo 2
30-40 = Gobo 3

This means anywhere between level 10-20 gobo 1 would be visible.  DMX512: 512 represent the number of channels one DMX cable can carry. It requires only 3 pins. Older systems, known as 5-core DMX may be seen - (two pins will not be used and are reserved for 2nd data link). The data is sent serially to 2 pins (the third is the ground pin) known as "positive phase" or "hot" and "negative phase" or "cold". Pins 4 & 5 are reserved for 2nd data signal or talkback. At the console end, the channels are fed into a multiplexer (mux) which takes the individual channel's data and encodes it into a format suitable for sending down the DMX line with all the other channels' data. At the dimmer/fixture end, the data is fed into a demultiplexer (demux) and split up again into the individual channels to be fed to individual dimming/function circuits. In practice, the mux and demux will be incorporated into the console and dimmers respectively, though standalone mux and demux units are available to convert analogue systems into DMX required.

The DMX advantage

DMX is advantageous because the DMX cable is less bulky than a 48-conductor cable and is cheaper and less cumbersome. If the cable were required to run long distances, any repeater/amplifiers would only have to amplify 2 signals instead of 48. DMX also allows control of many different pieces of DMX equipment, such as smoke machine, scanners, dimmers etc. from a central location.

Who publishes the standard?

The DMX 512 standard (Actually USITT DMX 512 - 1990) is published by The U.S.I.T.T. it is now maintained by ESTA for more info on standards go to ESTA.com

Wire and Electrical details

DMX 512 is RS485 serial at 250K baud, as such any installation must meet the requirements of EIA-485. In particular use of suitable good quality cable is important (Mic cable is NOT suitable) suitable cables include:

Belden 9841

Glossary:

 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

ACL :

Acronym for AirCraft Landing Light. A type of high intensity Par lamp that derives its name from its use as an aircraft landing lamp. The true ACL is 28V and 250W, although there are many variations. The lamp has a very tight beam.

 

ADAPTOR :

A Cable which allows two or more types of electrical connectors to be connected together.

 

ADDITIVE COLOR MIXING :

See Color Mixing.

 

AMP :

Abbreviation for:

1. AMPERE - the standard unit for measurement of electrical current passing through a circuit. Cables, fuses and switches are designated by their current carrying capacity. If a cable rated at 20 Amps is used with a load of 30 Amps, the cable will overheat and possibly catch fire.
2. AMPLIFIER - sound equipment that converts the low voltage, low current signal from a tape deck, mixer etc. into a higher current signal suitable for driving speakers.

 

 

ARC LIGHT :

See Discharge lamp.

 

ARCHITECTURAL LAMP :

A type of linear filament lamp with contacts at 90 degrees to the filament which can give the appearance of a continuous line of light (similar to neon, but dimmable).

 

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B

BACKLIGHT :

Light coming from upstage, behind scenery or actors, to sculpt and separate them from the background

 

BAFFLE :

1. A sheet of material used to prevent a spill of light in a instrument or in part of a set.
2. A panel in a loudspeaker cabinet designed to reduce back interference noise by isolating the front and rear of the loudspeaker diaphragm.

 

 

BALLAST :

A unit used in conjunction with discharge lamps(HMI) containing capacitors, inductors and other start-up circuitry. The inductor is initially used to develop a high potential to strike the discharge and is then used to limit the current flow while the lamp is lit.

 

BARNDOORS :

A rotatable attachment consisting of two or four metal flaps fixed to the front of a Fresnel or PC type lantern to reduce the beam spread in one or more directions.

 

BEAM ANGLE :

The angle of the cone of light produced by an instrument. Defined as the angle within which the lowest intensity in a beam of light from an instrument is not less than one-tenth of the maximum.

 

BLACK HOLE :

Accidentally unlit portion of the stage.

 

BLACK LIGHT :

See Ultra-Violet.

 

BLACKOUT :

Complete absence of stage lighting. Blue working lights backstage should remain on and are not usually under the control of the board, except during a Dead Blackout (DBO), when there is no onstage light. Exit signs and other emergency lighting must remain on at all times.

 

BLIND :

The facility on some light boards for the operator to make changes to the cues, without affecting the state on stage.

 

BLUES :

Blue lights used backstage in a performance situation. See also running lights.

 

BOARD :

The main control for the stage lighting. Originally known as the switchboard or dimmerboard, it is now usually remote from the dimmers. The lighting operator for a show is said to be "on the board".

 

BOOM :

1. Vertical scaffolding pole on which horizontal boom arms can be mounted, carrying instruments. Often used behind wings for side-lighting etc. Booms have a base plate or stand at the bottom and are tied off to the grid or fly floor at the top (not always necessary for short booms). Booms can also be fixed to the rear of the procenium arch (Pros. Boom) or hanging from the ends of battens. Sometimes known as a light tree.
2. An arm mounted on a microphone stand.

 

 

BOOM ARM :

See Boom.

 

BO'SUN'S CHAIR :

A small seat or cradle rigged on a rope over a pulley whereby a technician may be hoisted to work at an otherwise inaccessible position.

 

BRIDGE :

A walkway, giving access to technical and service areas above the stage or auditorium, or linking fly-floors.

 

BUILD :

1. During lighting plotting, to construct a state from blackout, or to add to an existing state.
2. An increase in light or sound level.
3. A period of set construction ("The Build")

 

 

BURN OUT :

An instrument that does not work due to a blown lamp.

 

BURNT OUT :

A colored filter that has lost its color or melted through due to excessive heat in front of a instrument. Dark blues and greens etc. are most susceptible, and may need replacing during a long run.

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C

 

CABLE :

Wiring, temporarily rigged, to carry electrical current. Depending on the size of the cable (current carrying capacity), cables are used to supply individual instructions, whole dimmer racks, or carry signals from a microphone etc.

 

CABLE TIE :

Lockable plastic strap used to tie a bundle of cables together, amongst many other things.

 

CAD :

Computer-Aided Design. Using a computer to help with 2D plans and drawings, or increasingly for 3D visualisation of how a set will look, and how lighting will affect it.

 

CATWALK :

An access walkway to equipment. Unlike a Bridge, not necessarily across a void.

 

C CLAMP :

Clamp on Yoke of most lighting units; requires a wrench to tighten.

 

CHANNEL :

A complete control path for signals in lighting or sound equipment.

 

CHANNEL CHECK :

The board operators job before a performance to make sure all lights are in working order.

 

CHASE :

A repeated sequence of changing lighting states.

 

CID (Compact Iodide Daylight) :

A high intensity discharge lamp that produces a light similar in color temperature to daylight approx. 5500K). A 1000W CID lamp produces 2.5 times more light than a 2000W tungsten halogen source

 

CIRCUIT :

1. The means by which a instrument is connected to a dimmer or patch panel. Numbered for reference.
2. A complete electrical "loop" around which current can flow.

 

 

CIRCUIT BREAKER :

An electro-mechanical "fuse" that can be reset, rather than having to be replaced. Available in the same ratings as fuses. 

 

COLOR :

See Color Filter.

 

COLOR CHANGER :

1. ) Scroller : A long string of up to 11 colours is passed horizontally in front of a instrument. Remotely controlled by the lighting desk.
2. ) Wheel : Electrically or manually operated disc which is fitted to the front of an instrument with several apertures holding different color filters which can be selected to enable color changes. Can also be selected to run continuously.
3. ) Boomerang : Manual semaphore-type device used on the front of a followspot.

 

 

COLOR FILTER :

A sheet of plastic usually composed of a colored resin sandwiched between two clear pieces. The colored filter absorbs all the colors of light except the color of the filter itself, which it allows through. For this reason, denser colors get very hot, and can burn out very quickly.

 

COLOR FRAME or Gel Frame :

A frame which holds the color filter in the guides at the front of a instrument. Many different sizes of frames are needed for the different instruments.

 

COLOR MIXING :

Combining the effects of two or more lighting filters ;

1. Additive : Focusing two differently colored beams of light onto the same area (eg Cyc Lights). Combining colors in this way adds the colors together, eventually arriving at white. The three primary colors additively mix to form white, as do the complementary colors.
2. Subtractive : Placing two different gels in front of the same instruments. Subtractive mixing is used to obtain a color effect that is not available from stock or from manufacturers. Because the ranges of color are so wide, the need for subtractive mixing is reducing. Combining colors in this way reduces the light towards blackness. The three primary colors mix subtractively to form black (or to block all the light).

 

 

COLOR TEMPERATURE :

A measure of the warmth or coolness of light sources and colors. Measured in degrees Kelvin. The human brain automatically compensates for different color temperatures - a film or video camera cannot, and thus what one sees as white may appear to have a blue or green tint when no color correction is used for video. Daylight is approximately 5600K and Tungsten Halogen is approx. 3200K.

 

COMPLEMENTARY COLORS :

Pairs of colors which, when additively mixed, combine to produce white light. Examples are red + cyan, green + magenta, and yellow + blue. 

 

CROSS FADE :

Bringing another lighting state up to completely replace the current lighting state. Also applies to sound effects / music. Sometimes abbreviated to Xfade or XF.

 

CUE :

The command given to technical departments to carry out a particular operation. E.g. Fly Cue or Sound Cue. Normally given by stage management, but may be taken directly from the action (i.e. a Visual Cue).

 

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D

 

DAISY-CHAINING :

Connecting items of equipment together by linking from one to the next in a chain. Used for connecting demux boxes to dimmers etc.

 

DBO (Dead Blackout) :

See Blackout.

 

DEAD :

1. Scenery or equipment not needed for current production - "that table's dead".
2. An electric circuit that has been switched off or has failed.

 

 

DICHROIC FILTER :

Glass color filters which reflect all light except that which is the color of the filter, which passes through. Normal gels absorb the unwanted colors, turning the light into heat. Dichroic filters run cooler, and produce a much cooler beam of light. Longer lasting, but a lot more expensive.

 

DIGITAL DIMMER :

The new generation of dimmers that can respond directly to the digital multiplexed output of the lighting desk. The technology also permits the dimmer to report faults and other data back to the control board.

 

DIMMER :

Electrical or electronic device which controls the amount of electricity passed to an instrument, and therefore the intensity of the lamp.

 

DIMMER RACK :

A number of individual dimmer circuits mounted in a cabinet.

 

DIP :

1. Low lighting intensity when cross fading between two higher states.
2. Transparent lacquer for coloring lamps.

 

 

DISCHARGE LAMP :

A high-powered source of light produced by means of a discharge between two electrodes. An arc light, for example uses a discharge between two carbon rods which are manually or automatically fed together as they are burnt up. The use of this type of lighting is restricted to non-dimming applications such as followspots and projection, where dimming is achieved by mechanical means. Many of the new generation of moving lights use discharge lamps and dichroic filters. See Ballast, CSI, CID, MSR, HMI, HTI, Xenon, MBI.

 

DISTRIBUTION PANEL:

System of interconnected fuse carriers and cabling that routes an incoming power supply to a number of different outputs.

 

DMX512 :

An EIA-485 based communications protocol most commonly used to control stage lighting and effects.  en.wikipedia.org/wiki/DMX512-A

 

DOWSER :

A metal flag used in larger followspots and projection equipment to cut off the light beam without cutting off the electrical supply. Discharge lamps need a period of cooling down when they are turned off before they can be turned on again, so they should not be switched off if needed again within two hours.

 

DRY ICE :

Frozen solid carbon dioxide (CO2) at a temperature of -87.5 degrees centigrade which produces clouds of steam-loaded CO2 gas forming a low-lying mist or fog when dropped into boiling water. Although non-toxic, caution is required in the storage and handling of dry ice because of its extreme cold. Water is boiled in a large tank offstage, into which the dry ice is lowered in a basket. Fans and ducts then direct the gas onto the stage. Dry ice does not support life, so care should be taken that small animals, actors etc. are not below the level of the dry ice for more than a few seconds.

 

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E

 

EFFECTS, LIGHTING :

1. Animation Disc : A slotted or perforated metal disc which rotates in front of a instrument to provide "movement" in the light. Most effective when used in front of a profile carrying a gobo.
2. Effect Disc : A painted glass disc rotating in front of an effects projector with an objective lens to focus the image (eg Flames, Rain, Snow).
3. Flicker Flame : Irregularly slotted rotating metal disc through which light is shone onto a prism-type piece of glass which scatters the beam of light and adds the "dancing" effect of firelight to a scene.
4. Gobo Rotators : Motorized device inserted into the gate of a instrumnet that can be remotely controlled to rotate a gobo, usually with variable speed and direction.
5. Lightning : Created through the use of either strobe sources or photoflood lamps.

 

EFFECTS PROJECTOR :

Instrument used to project the image from a rotating glass effects disc. Used with an objective lens to produce the desired size of image. Commonly used discs are clouds, flames and rain.

 

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F

 

FADER :

A vertical slider which is used to remotely set the level of a lighting or sound channel. A fade is an increase, diminishment or change in lighting or sound level.

 

FEED :

A power supply to a piece of equipment or installation is termed a "feed". Sound equipment and sensitive computer equipment should have a clean feed - that is, a supply free from interference from other equipment.

 

FIBER OPTIC :

A method of directing light down a very thin glass fiber. Fiber Optics are used mostly in communication, but find theatre applications in star cloths which are black backcloths with the ends of optical fiberspoked through, to create a mass of pin pricks of light. A large bundle or harness of fibers may be fed from one light source, sometimes with a motorised color or flicker wheel.

 

FIELD :

Refers to the spread of light intensity across a beam. Most instruments have an adjustable field. A Flat field has an even distribution, a peak field has a "hot spot" in the center of the beam. A flat field is essential when using gobos.

 

FILL LIGHT :

Light which fills the shadows that key light creates. (especially TV and film lighting)

 

FILTER :

1. ) See Color.
2. Electronic device to isolate and redirect specific frequencies in a speaker system.

 

FLASH BOX :

A small box containing the socket into which a pyro cartridge is plugged. Also known as a flash pot.

 

FLOOD :

1. A lensless instrument that produces a broad non-variable spread of light.
2. To increase the beam size of a focus spot by moving the lamp and reflector towards the lens in Fresnels. "Flood that a bit, please !"

 

FLUORESCENCE :

The property of some materials to glow when subjected to Ultra-violet light. The materials degrade the UV wavelengths into longer and therefore visible reflected rays. See also Phosphorescence.

 

FOCUS:

 

 

FOCUSING :

The process of adjusting the direction and beam size of instrumnets. Does not necessarily result in a "sharply focused" image.

 

FOCUS SPOT :

Term for Fresnel.

 

FOLLOW SPOT :

Usually, a powerful instrument usually fitted with its own dimmer, iris, color magazine and shutters mounted in or above the auditorium, used with an operator so that the light beam can be moved around the stage to follow an actor.

 

FRESNEL :

Pronounced "Fre-nell") A type of instrument which produces an even, soft-edged beam of light through a Fresnel lens. The lens is a series of stepped concentric circles on the front and pebbled on the back and is named after its French inventor, Augustin Jean Fresnel (1788-1827).

 

FUSE :

Protective device for electrical equipment (E.g. dimmers). The fuse link will melt when excess current flows, preventing damage to people or equipment. Every piece of electrical equipment has at least one fuse in its associated circuit.

 

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G

 

GAFF TAPE :

Ubiquitous sticky cloth tape. Most common widths are .5" for marking out areas and 2" (usually black) for everything else. Used for temporarily securing almost anything. Should not be used on coiled cables or equipment.

 

GEL :

See Color Filter.

 

GERB :

See Pyro.

 

GOBO :

A thin metal plate etched to produce a design which can then be projected by a profile spotlight (E.g. Foliage, Windows). The image can be used soft focus to add texture, rather than a defined image. A number of composite gobos in different colored instruments can, with careful focusing, produce a colored image (e.g. a stained glass window). Greater detail can be achieved using a glass gobo. The original use of the word GOBO came from the early days of Hollywood. When the Director of Photography wanted daylight excluded from some area of the set, he'd say "GO BlackOut". Loads of people would run around putting black material between the sun and the set. It eventually evolved into other stuff that goes in front of lights and now most commonly refers to patterns in instruments.

 

GOBO HOLDER :

A metal plate designed to hold a gobo of a particular size in an instrument of a particular type.

 

GOBO ROTATOR :

See Effects.

 

GRAND MASTER :

See Master.

 

GRID :

 

1. The support structure close to the top of the fly loft on which the pulleys of the fly system are supported. Constructed from metal or wooden beams.
2. Arrangement of scaffolding from which instruments are hung in a performance space with no flying facilities.

 

GROUNDING :

Electrical safety requirement that metal parts of electrical equipment are connected to a common earth or ground point so that in the event of a fault, excess current can be carried away, causing the fuse to blow.

 

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H

 

HALOGEN CYCLE :

Chemical process occurring in Tungsten Halogen lamps which makes them possible. During the lamps life, Tungsten evaporates from the filament, and would normally deposit itself on the glass wall of a Tungsten lamp, causing it to blacken, and causing the output of the lamp to reduce until it finally blew. In a Tungsten Halogen lamp, the Tungsten combines with the Halogen gas elements present in the lamp envelope and is re-deposited back onto the filament. This process needs a very high temperature to operate, so Tungsten Halogen lamps are able to be a lot smaller, and run a lot hotter, than their Tungsten equivalents. See also Tungsten Halogen.

 

HMI (Hydragyrum Medium arc-length Iodide) :

A mercury-halide discharge lamp with a color temperature of 5600K (daylight).

 

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I

 

INCANDESCENT :

Light source consisting of a metal filament (Tungsten) which glows white hot when current is passed through. See also Discharge Lamp

 

INDEPENDENT :

1. An electrical power supply that is totally separate from the stage lighting control. Used for testing lanterns prior to connection to the lighting system and also for powering non-lighting equipment on stage and working lights. See Non Dim.
2. A channel within the stage lighting control that has been temporarily switched to become independent from the rest of the channels which remain under control of the operator.

 

INFRA RED :

Invisible part of the electromagnetic spectrum with a longer wavelength than visible light. Infra-red remote controls are used for lighting desks and practicals. An infra-red-sensitive CCTV camera can pick up body heat activity even in a "blackout". 

 

INSTRUMENT :

1. General term for unit of lighting equipment including spotlight, flood etc. Term now being replaced by the internationally recognised "luminaire".
2. Glazed section of roof usually in haystack form over the fly tower that automatically opens in the case of fire. An updraught is created which inhibits fire from spreading quickly into the auditorium, and prevents build-up of smoke at stage level.

 

INTELLIGENT LIGHT :

See Moving Light.

 

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J

 

JUMPER :

An adaptor from one type of electrical connector to another. For example, a 13 - 15A jumper has a 13A plug and a 15A socket at either end of a short cable. Also applicable to sound cables.

 

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K

 

KELVIN :

See Color Temperature.

 

KILL :

To switch off (a light/sound effect); to strike/remove (a prop).

 

KILOWATT :

1 kilowatt (1kW) is equal to 1000 Watts

 

KVA :

Kilo-Volt Amps. Unit of electrical power.

 

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L

 

LAMP :

Light bulb.

 

LASER :

Acronym of Light Amplification by Stimulated Emission of Radiation. A very high energy beam of light that remains virtually parallel throughout its length. Visible in the air only when a haze of smoke or dust is introduced. Great care is required when using lasers as this energy can cause permanent damage to the retina of the eye.

 

LD :

Lighting Designer.

 

LENS :

Optical glass with one or both sides curved, the purpose of which is to direct light by concentrating or dispersing light beams. 

 

LOAD :

1. The electrical power rating (in Watts) of the equipment connected to a particular lighting dimmer.
2. The equipment connected to a dimmer.

 

LOW VOLTAGE :

Lower voltage lamps give more intense light than mains voltage lamps of the same wattage.

 

LUMEN :

A measure of light output from a source.

 

LUMINAIRE :

The international term for lighting equipment. Not restricted to theatre lighting.

 

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M

 

MASKING :

Neutral material or designed scenery which defines the performance area and conceals the technical areas. (e.g. Masking flat).

 

MASTER :

1. An overall control on a lighting or sound control board. The Grand Master takes precedence over all other controls. See Submaster.
2. An original (e.g. Master tape, master plan) which should be used only to make a copy from which to work.
3. A Department Head (e.g. Master Carpenter, Master Electrician).

 

MASTER  ELECTRICIAN :

The senior member of the theatre's stage lighting team, although not necessarily the lighting designer.

 

MEMORY BOARD :

An electronic storage device which enables recording and subsequent "playback" of lighting states.

 

MIDI :

Musical Instrument Digital Interface. Control system for linking musical instruments or other electronic equipment and computers together and storing the control signals the equipment produces for subsequent playback. See MSC and MMC.

 

MIRROR BALL :

A lighting effect popular in ballrooms and other dance halls. A large plastic ball covered with small mirror pieces. When a spotlight is focused onto the ball, specks for light are thrown around the room. Usually motorized to rotate.

 

MODEL :

A scale model provided by the set designer to help all the technical departments to co-ordinate and plan a production. Used as a reference when building, painting, dressing and lighting the set.

 

MONITOR :

1. An onstage speaker which allows a performer to hear the output of the PA system, or other members of a band.
2. A video display screen

 

MSC :

MIDI Show Control. A control language which is an extended version of the original MIDI language. In addition to a "go" command, cue numbers and other information can be sent as well (in addition to fault reports and safety checks).

 

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N

 

NEON :

1. A type of discharge lighting generated by a high voltage across two electrodes at opposite ends of a long, thin glass tube filled with neon gas. Different colors can be obtained by mixing other gases, or by using fluorescent coatings. Mostly used for advertising signs - the glass tube is bent to form letters.
2. A small mains voltage indicator lamp. 

 

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O

 

OHM :

The unit of electrical resistance.

 

OPEN WHITE (o/w) :

Lighting with no color filter.

 

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P

 

PAR :

Short for Parabolic Aluminized Reflector lamp. A lamp containing a filament, reflector and lens in one sealed unit. Used in Parcans to produce a high intensity narrow beam of light. Par lamps are available in many different sizes and powers. Par sizes available include 16, 36, 38, 56 and 64. (The number refers to the diameter of the lens, in eighths of an inch).

 

PHASES :

Electricity is generated and supplied to large installations in three phases. Each of the Red, Black and Blue phases are supplied down one cable to the building, but effectively give three separate supplies. Because there is a potential difference (voltage) of 208 volts (UK) between two phases, care must be taken that pieces of equipment powered by different phases are not capable of being touched at the same time in case of a fault.

 

PHOSPHORESCENCE :

The property of some materials that can store light energy and glow in the dark.

 

PIN SPOT :

1. An instrument focused very tightly on a small area. (e.g. an actors head)
2. An instrument used widely in disco installations, consisting of a low voltage Par 36 lamp with a fine beam in a metal case with built in transformer.

 

PRESET :

1. Anything in position before the beginning of a scene or act (eg Props placed on stage before the performance, lighting state on stage as the audience are entering.)
2. An indepenently controllable section of a manual lighting board which allows the setting up of a lighting state before it is needed. Each preset has a master fader which selects the maximum level of dimmers controlled by that preset.

 

PRIMARY COLORS :

The primary additive colors of light are red, green and blue, and the subtractive colors are cyan, magenta and yellow.

 

PRODUCTION MANAGER :

Person responsible for technical preparations, including budgeting and scheduling of productions.

 

PROFILE :

Shaped piece of scenery added to the edge of a flat instead of a straight edge. Also known as a cutout.

 

PROJECTION :

1. Lighting effects : Moving cloud / rain / fire effects can be achieved using a powerful lantern known as an effects projector with a motorised glass disc painted with the required effect. An objective lens is required in front of the disc to focus the image. See Effects.
2. Gobos : See Gobo.

 

PSU :

Power Supply Unit.

 

PYROTECHNICS :

(Pyro) Chemical explosive or flammable firework effects with a manual detonation. Usually electrically fired with special designed fail-safe equipment. Types of pyro range from the Theatrical Flash (a flash and a cloud of smoke) to the Maroon (which produces a very loud bang). A Gerb is a version of the Roman Candle firework, throwing a shower of sparks into the air. All pyrotechnics should be used with close reference to local licensing laws, and the manufacturers instructions.

 

PVC TAPE :

Plastic insulating tape used for taping cables to bars and for securing coiled cables. Neater and cheaper than Gaffa tape. Also known as electrical tape.

 

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Q

 

QUARTZ HALOGEN :

See Tungsten Halogen.

 

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R

 

RACK :

A cabinet of standard width (19") into which various components can be bolted. Racks are ideal for touring equipment, are neat, and they allow easy access to the rear and front panels.

 

RIG :

1. (noun) The construction or arrangement of lighting equipment for a particular production.
2. (verb) Installing lighting, sound equipment and scenery, etc. for a particular show.

 

 

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S

 

SAFETY CHAIN :

Chain or wire fixed around lantern and lighting bar or boom to prevent danger in the event of failure of the primary support (e.g. Hook Clamp).

 

SCRIM :

Cloth with a relatively coarse weave. Used unpainted to diffuse a scene played behind it. When painted, a scrim is opaque when lit obliquely from the front and becomes transparent when the scene behind it is lit . Many different types of scrim are available; Sharkstooth gauze is the most effective for transformations, because it is the most opaque. Vision scrim is used for diffusing a scene and for supporting cut cloths.

 

SECONDARY LIGHTING:

Separately powered lighting system for use throughout the building in the event of failure of the primary system. Usually battery powered. Maintained lighting is on all the time, regardless of changes in the stage lighting, and is battery backed-up.

 

SERIES SPLITTER :

An adaptor consisting of a plug and two sockets wired in series. Enables two identical 110 Volt loads to be safely run from a 240 Volt supply (UK).

 

SMOKE MACHINE :

Electrically powered unit which produces clouds of white non-toxic fog (available in different flavors/smells) by the vaporization of mineral oil. Specially designed for theatre & film use. Vital for revealing airborne light beams. See Cracked Oil, Dry Ice.

 

SPLITTER :

See Adaptor.

 

SPOTLIGHT :

General term for any lantern with a lens system.

 

STAGE LEFT / RIGHT :

Left/ Right as seen from the Actor's point of view on stage. (i.e. Stage Left is the right side of the stage when looking from the auditorium.)

 

STEP :

A control on some lighting effects boards which enables the operator to "step" through a chase effect in time to music etc.

 

STRIKE :

To take down a setting; to take down properties or instruments.

 

STRIPLIGHT :

A thin linear filament lamp similar to an Architectural, but having contacts at the ends of the lamp. Available clear or opaque.

 

STROBE :

Device giving a fast series of very short intense light flashes which can have the effect of making action appear intermittent. Because strobe lighting can trigger an epileptic attack in sufferers, the use of a strobe must be communicated to the audience before the performance begins. Regulations exist governing the maximum length of time for which a strobe can be used.

 

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T

 

THROW :

Distance between a light source (e.g. lantern or projector) and the actor or object being lit.

 

TRUSS :

A framework of alloy bars and triangular cross-bracing (usually of scaffolding diameter) providing a rigid structure, particularly useful for hanging lights where no permanent facility is available.

 

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U

 

ULTRA VIOLET (UV) :

Short wavelength source of light at the end of the visible light electromagnetic spectrum which causes specially treated materials to fluoresce on an otherwise blackened stage. Used for special effect and for lighting onstage technical areas (e.g. Fly Floors). Ultraviolet sources designed for stage use are known as Black Light sources and have all harmful radiations filtered out.

 

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V

 

VOLTAGE :

The pressure at which electric current is available. The UK standard voltage is 240 Volts. The American standard is 110 Volts.

 

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W

 

WATTS :

Unit of electrical power derived from the current (or "quantity" of electricity) multipled by the voltage (or "pressure" at which the current is delivered). Stage lighting equipment is rated in Watts (or Kilowatts - 1kW being equal to 1000W). This refers to the amount of power required to light the lamp. A higher wattage lamp requires more power and gives a brighter light output.

 

WORKING LIGHTS :

1. High wattage lights used in a venue when the stage / auditorium lighting is not on. Used for rehearsals, fit-up, strike and resetting.
2. Low wattage blue lights used to illuminate offstage obstacles and props tables etc. Known as Wing Workers.

 

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X

 

XFADE :

See Cross Fade.

 

XLR :

Multipin metallic audio connector. (3 pin for normal sound use, 5 pin for DMX, Color Scrollers etc). Sometimes called Cannons after the original manufacturer. See balanced line. The UK standard for wiring the 3 pin connector is as follows : Pin 1 (Ground), Pin 2 (+ve / "cold"), Pin 3 (-ve, "hot").

 

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Y

 

YOKE :

The TRUNNION ARM of a lantern.

 

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Z

 

 

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Belden 9842

Alpha 5274 This is not a complete list. 

Wiring practice

At the speed DMX works correct wiring practice is important. Always arrange wiring such that the data source is at one end of the cable. Never use an Y connector but rather a DMX splitter.

Line termination

All DMX lines must be correctly terminated if reliable operation is to be obtained. If not, signal loss can occur.  Some fixtures have a switchable line-terminating resistor built in. In these cases make sure that only the last item in the chain has its terminating switch set to the on position. If the last item (Farthest from data source) does not have a terminating switch then an external line-terminating network is needed. To make one you will need the following parts:

1 Male 3 Pin XLR.

1 110 ohm 0.5W resistor.

To make the line terminator solder the resistor across pins 2 and 3 of the XLR. You may like to back fill the XLR with epoxy resin to provide protection. Line termination will not correct a bad cable or interference from running a DMX cable next to an electrical cable. High power electrical cables will cause interference.  What is addressing?

Because the DMX protocol is so basic, each intelligent light's range of controlling DMX channels must be set manually. Each light's DMX address corresponds to the first of the light's channels.

For example:

If you have two intelligent lights that use five channels each. You set the DMX address of the first to 1 and the second to 6. Now, the first light is using channels 1,2,3,4, and 5; and the second is using 6,7,8,9, and 10.  You may also have to setup your intelligent light console for the type of lights you have and setup their DMX addresses on the console before you can control them.

Addressing Planning

You may want to do a little planning before you start addressing your lights. Put all your lights in a logical order; it will help you figure out which light is which later. Next, find out how many DMX channels each type of light you have uses. The light's manual should tell you this. Now that you know what channel to start addressing your lights at, you can figure each light's DMX address (except when your controller banks channels see Controllers). Take the first light's DMX address, add the number of channels it uses, and you have the second light's DMX address. Then, take the second light's DMX address, add the number of channels it uses, and you have the third light's DMX address. Do this until you have all the DMX address for your lights written down.

Controllers

Some controllers (ShowXpress) give you settings automatically and some controllers use banks of channels.  Whether your fixture uses 4 DMX channels or 10 DMX channels it will still require you to set up your fixtures based on it banks.

Example:

CX-5 banks all fixtures in 14 channel intervals so your first fixture would always start on channel 1 and fixture 2 will always start on channel 15.

DMX-40 banks all fixtures in 16 channel intervals so your first fixture would always start on channel 1 and fixture 2 will always start on channel 17. DMX-40 has no joy stick there for you can use all the channels.

ShowXpress allows you to use all the channels

Setting dip switches

Read your fixture's manual to find out how to address your light. Many intelligent lights use binary dipswitches, while others lights may use a small display and buttons to set the DMX address. When using dipswitches there is always a minimum of 9 dipswitches. Each dipswitch has a value as listed below. If the first light starts at channel 1 (dip 1 on) and your second light starts at channel 40 (dip 4, 6 are on). Exception: if your controller works in banks of 14 you first fixture would start on channel 1 (dip 1 on) and 2nd fixture would start on channel 15 (dip 1,2,4,8 on) etc....

1=1

2=2

3=4

4=8

5=16

6=32

7=64

8=128

9=256

Some fixtures have more then 9 dipswitches. 10 will always be a standalone function/ focus/ invert/self test etc....