Who publishes the standard?

The DMX 512 standard (Actually USITT DMX 512 - 1990) is published by The U.S.I.T.T. it is now maintained by ESTA for more info on standards go to ESTA.com

Wire and Electrical Details

DMX 512 is RS485 serial at 250 Kbaud, as such any installation must meet the requirements of EIA-485. In particular use of suitable good quality cable is important (Mic cable is NOT suitable) suitable cables include: Belden 9841 Belden 9842 Alpha 5274 This is not a complete list.

Wiring practice

At the speed DMX works correct wiring practice is important. Always arrange wiring such that the data source is at one end of the cable. Never use an Y connector but rather a DMX splitter.

Line termination

All DMX lines must be correctly terminated if reliable operation is to be obtained. If not, signal loss can occur. Some fixtures have a switchable line-terminating resistor built in. In these cases make sure that only the last item in the chain has its terminating switch set to the on position. If the last item (Farthest from data source) does not have a terminating switch then an external line-terminating network is needed. To make one you will need the following parts: 1 Male 3 Pin XLR. 1 110 ohm 0.5W Resistor. To make the line terminator solder the resistor across pins 2 and 3 of the XLR. You may like to back fill the XLR with epoxy resin to provide protection. Line termination will not correct a bad cable or interference from running a DMX cable next to an electrical cable. High power electrical cables will cause interference.

Previous Page (1/4) - Next Page (3/4)

[ Go Back ]

Lighting