Chauvet DMX Primer Manual De Instrucciones página 3

DMX Primer EN
(DMX Connectivity cont.)
Number of Products
DMX Data Cabling
Making Your Own DMX
Cable
DMX Cable
Characteristics
DMX Cable Connectors
DMX Primer Rev. 8
When using a DMX controller, the combined number of channels required by all
the products on the DMX daisy chain determines the number of products the DMX
controller has to support. Conversely, the number of onboard sliders, page
buttons, and product buttons limits the number of discrete DMX channels a DMX
controller can support.
To comply with the EIA-485 standard, which is the base for the USITT
DMX512-A protocol, do not connect more than 32 products without using an
optically-isolated DMX splitter. Doing otherwise may result in deterioration
of the digital DMX signal.
Use DMX-compliant data cables to link two or more DMX-compatible products.
You may purchase CHAUVET® certified DMX cables directly from a
dealer/distributor or construct your own cable.
USITT recommends limiting the total length of the DMX cable (from the first
product/controller to the last product) to 300~455 m (985~1,500 ft).
If you choose to create your own DMX cable, make sure to use data-grade cables
that can carry a high frequency signal and are less prone to electromagnetic
interference. Use a Belden® 9841 or equivalent cable, which meets the
specifications for EIA RS-485 applications. For certain applications, Cat5, Cat5e,
or Cat6 may be appropriate.
Do not use standard microphone cables for DMX applications because they
cannot transmit DMX data reliably over long distances.
The DMX data cable must have the following characteristics:
Type:
Maximum capacitance between conductors:
Maximum capacitance between conductor and shield:
Maximum resistance:
Nominal impedance:
Each DMX cable must have a male (3-pin or 5-pin XLR connector) on one end
and a female (3-pin or 5-pin XLR connector) on the other end.
DMX Connector Configuration
To DMX Input
(Female)
1
3
2
To avoid signal transmission
problems and interference,
connect a DMX signal terminator
to the last product in the
DMX daisy chain, as shown.
shielded, 2-conductor twisted pair
To DMX Output
(Male)
Common
DMX +
DMX -
1
3
2
30 pF/ft
55 pF/ft
20 ohms/1000 ft
100~140 ohms
1
3
2
120 ohm, ¼ W
resistor between
pin 2 (DMX -) and
pin 3 (DMX +) on
the output of the
last product.
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