DMX Mega Strobe™ III User Manual
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6/11/2009 1:02 PM
Fixture Linking
You will need a serial data link to run light shows of one or more fixtures using a DMX-512 controller
or to run synchronized shows on two or more fixtures set to a master/slave operating mode. The
combined number of channels required by all the fixtures on a serial data link determines the number
of fixtures the data link can support.
Important:
Fixtures on a serial data link must be daisy chained in one single line. To comply with
the EIA-485 standard no more than 32 fixtures should be connected on one data link.
Connecting more than 32 fixtures on one serial data link without the use of a DMX
optically-isolated splitter may result in deterioration of the digital DMX signal.
Maximum recommended serial data link distance: 500 m (1640 ft)
Maximum recommended number of fixtures on a serial data link: 32
Data Cabling
To link fixtures together you must obtain data cables. You can purchase CHAUVET-certified DMX
cables directly from a dealer/distributor or construct your own cable. If you choose to create your own
cable please use data-grade cables that can carry a high quality signal and are less prone to
electromagnetic interference.
DMX Data Cable
Use a Belden© 9841 or equivalent cable which meets the specifications for EIA RS-485 applications.
Standard microphone cables cannot transmit DMX data reliably over long distances. The cable must
have the following characteristics:
2-conductor twisted pair plus a shield
Maximum capacitance between conductors
– 30 pF/ft.
Maximum capacitance between conductor and shield
– 55 pF/ft.
Maximum resistance of 20 ohms / 1000 ft.
Nominal impedance 100
– 140 ohms
Cable Connectors
Cabling must have a male XLR connector on one end and a female XLR connector on the other end.
CAUTION
Do not allow contact between the common and the fixture’s chassis ground.
Grounding the common can cause a ground loop, and your fixture may perform
erratically. Test cables with an ohmmeter to verify correct polarity and to make sure
the pins are not grounded or shorted to the shield or each other.
COMMON
DMX +
DMX
-
INPUT
OUTPUT
1
3
2
1
3
2
1
3
2
Resistance 120
ohm ¼ W between
pin 2 (DMX -) and
pin 3 (DMX +) on
the output of the
last fixture.
To avoid signal transmission
problems and interference, it is
always advisable to connect a DMX
signal terminator.
DMX connector configuration
