Osram AS 330, Руководство пользователя

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Chapter 4 !
DMX Programming Basics
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DMX Programming Overview
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DMX512 Links
A lighting console typically uses a DMX512 protocol to communicate with automated lighting
fixtures and conventional dimmers. This protocol consists of 512 unique channels of control per
output link (universe). Typically a lighting fixture or device will use a channel for each
parameter’s function. Each channel consists of 256 values ranging from 0 to 255. The lighting
console is programmed to transmit a corresponding DMX value for the desired function of each
parameter. All DMX values are stored within in the lighting console, and typically are referred
to as cues, scenes, or presets. A lighting console locates a device on the link by it’s DMX Start
Channel.
8-bit vs. 16-bit DMX Parameters
Most parameters of an automated light use one channel of DMX providing 256 values of control
(0-255). This is known as 8-bit DMX. Although most parameters use 8-bit DMX, several require
a more accurate range of values than can be provided with a single DMX channel.
By utilising two DMX channels for a single parameter, 65535 values become available for
controlling and adjusting parameter functions. This is known as 16-bit DMX. You can adjust 16-
bit DMX values in both coarse and fine increments. The first channel of the pair provides
coarse control changes of the DMX value in increments of 256. The second channel provides
fine control and changes of the DMX value in increments of 1.
Individual access of the two DMX channels used with 16-bit parameters varies by lighting
console. Most modern DMX consoles bind these two channels into a single 16-bit parameter to
accurately perform 16-bit crossfades. Consult your lighting console manual for further
information.
Determining a DMX Start Channel
The DMX Start Channel is the first channel of a device’s channel range on a DMX link. There
are 512 available channels on each DMX universe divided among all the devices in a particular
universe. A device must have a unique DMX Start Channel number in order to respond
independently to controller commands.
To determine each device’s DMX Start Channel, identify the footprint of every device on the
universe. The device’s footprint is the number of consecutive DMX channels a device requires
and is determined by the channels in the fixture’s protocol. The fixture’s DMX channel range
must not overlap any other device’s channel range on the link. When two devices on the same
DMX universe have overlapping channel ranges, one or both devices will be disabled or behave
erratically.
Select the protocol level in the fixture’s onboard menu system. The tables on the following
pages list the parameters included in each protocol mode.
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Conic Lighting Designs TM - Luminaire User Manual ! ! ! ! ! ! ! ! 15