Follow these helpful rules while using DMX:

  1. Up to 32 devices may be connected in a single daisy chain, with a terminator on the last device. Using a DMX splitter/repeater can extend both cable distance (as the signal is regenerated and retransmitted) and the number of devices (up to 32 per branch). 
  2. Up to 300 meters, DMX cable should be run to a maximum of 300 meters when using DMX cable before using a splitter or booster. Past this, the signal can degrade.  
  3. 5-Pin XLR Plugs DMX officially supports 5-Pin XLR DMX cables only. However, there are readily available 3-pin XLR converters, but it is essential to ensure these are DMX compatible (correct pin-out).  DO NOT USE Microphone/audio Cables Many people often substitute cheaper balanced audio cable (regular microphone cable) with bad results. Audio cable cannot support the signal rate required by the high-speed DMX protocol. While the signal may pass over short distances, it is highly susceptible to interference and degradation given its different resistance, causing unpredictable results (blinking lights, unpredictable behaviour, etc.). 
  4. Never Y-Split DMX Data: DMX data should never be Y-Split to stop data bounce back or clashes. – Always use a DMX buffer or splitter. 
  5. Use DMX Terminators If you have set up your devices in a daisy chain: the final device in the daisy chain must be terminated. The terminator absorbs signal power which would otherwise be reflected back into the cable and degrade the data. A terminator simply places a 110-120 Ohm, 0.5 Watt resistor across the two transmission wires. 
  6. Isolate DMX from power Connect all intelligent lighting fixtures to a separate mains power source where possible that is fully isolated from the dimmer racks or computer or the audio power amps. Unexpected events might occur if the mains electricity gets too much electrical “noise” on it that might affect your DMX control gear. 
  7. Importance of Isolated Splitters Use an optoisolated splitter to protect your DMX control gear from any unwanted voltage spikes that could potentially make their way into the DMX line. Non-isolated DMX control devices must always be protected, otherwise they run the risk of being subject to damage caused by sudden voltage spikes. 

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