5. Appendix
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12/28/2009 12:38 PM
5.
A
PPENDIX
DMX Primer
There are 512 channels in a DMX connection. Channels may be assigned in any manner. A fixture
capable of receiving DMX will require one or a number of sequential channels. The user must assign
a starting address on the fixture that indicates the first channel reserved in the controller. There are
many different types of DMX controllable fixtures and they all may vary in the total number of
channels required. Choosing a start address should be planned in advance. Channels should never
overlap. If they do, this will result in erratic operation of the fixtures whose starting address is set
incorrectly. You can however, control multiple fixtures of the same type using the same starting
address as long as the intended result is that of unison movement or operation. In other words, the
fixtures will be slaved together and all respond exactly the same.
DMX fixtures are designed to receive data through a serial Daisy Chain. A Daisy Chain connection is
where the DATA OUT of one fixture connects to the DATA IN of the next fixture. The order in which
the fixtures are connected is not important and has no effect on how a controller communicates to
each fixture. Use an order that provides for the easiest and most direct cabling. Connect fixtures
using shielded two conductor twisted pair cable with three pin XLR male to female connectors. The
shield connection is pin 1, while pin 2 is Data Negative (S-) and pin 3 is Data positive (S+).
General Maintenance
To maintain optimum performance and minimize wear, fixtures should be cleaned frequently. Usage
and environment are contributing factors in determining frequency. As a general rule, fixtures should
be cleaned at least twice a month. Dust build up reduces light output performance and can cause
overheating. This can lead to reduced lamp life and increased mechanical wear. Be sure to power off
fixture before conducting maintenance.
Unplug fixture from power.
Use a vacuum or air compressor and a soft brush to remove dust collected on external
vents.
Clean all glass when the fixture is cold with a mild solution of glass cleaner or Isopropyl
Alcohol and a soft lint free cotton cloth or lens tissue.
Apply solution to the cloth or tissue and drag dirt and grime to the outside of the lens.
Gently polish optical surfaces until they are free of haze and lint.
The cleaning of external optical lenses and/or mirrors must be carried out periodically to optimize light
output. Cleaning frequency depends on the environment in which the fixture operates. Damp, smoky
or particularly dirty surroundings can cause greater accumulation of dirt on the unit’s optics. Clean
with soft cloth using normal glass cleaning fluid. Clean the external optics at least every 20 days.
Clean the fixture at least every 30/60 days.
Always dry the parts carefully after cleaning them.
Never spin a fan using compressed air.
