Appendix; Dmx Primer; General Troubleshooting - Venue Tetra 6 Manual

APPENDIX

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 will all respond exactly the
same. Consult the Owner's Manual to your DMX controller for more information.
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 Troubleshooting

SYMPTOM
Breaker/Fuse keeps blowing
Device does not power up
Fixture is not responding to DMX
Loss of signal
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POSSIBLE CAUSE(S)
• Excessive circuit load
• Short circuit along the power wires
• No power
• Loose power cord
• Wrong DMX addressing
• Damaged DMX cables
• Wrong polarity settings on the controller
• Loose DMX cables
• Faulty DMX interface
• Faulty Main PCB
• Non DMX cables
• Bouncing signals
• Long cable / Low level signal
• Too many fixtures
• Interference from AC wires
POSSIBLE ACTION(S)
• Check total load placed on the electrical circuit
• Check for a short in the electrical wiring (internal and/
or external)
• Check for power on Mains
• Check power cord
• Check Control Display and unit addressing
• Check DMX cables
• Check polarity switch settings on the controller
• Check cable connections
• Replace DMX input
• Replace Main PCB
• Use only DMX compatible cables
• Install terminator as suggested
• Install amplifier right after fixture with strong signal
• Install an optically coupled DMX splitter after unit #32
• Keep DMX cables separated from power cables or
black light
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