Leprecon VX Dimmer - Manual (Page 7)

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4.1. DMX 512
One of the best features of modern lighting equipment is the use of digital communication
between control boards and dimmers. The low cost of the cable and connectors in a digital
system makes a substantial difference in system cost. With the adoption of DMX 512 by the
industry, compatibility is assured between products offered by different manufacturers.
All Leprecon VX dimmers are compatible with DMX 512. To connect the VX dimmer to a DMX
controller, simply use a standard DMX cable and plug the two devices together. A parallel wired
female connector is supplied to allow output to additional dimmers or other devices.
4.1.1. DMX Load
VX dimmers, along with other digital dimmers manufactured by Leprecon, includes optical
isolation at the DMX input. This design greatly reduces the chances of failure in the dimmer
causing incidental damage to the control console, or other dimmers in the system. The load
presented to the DMX line is greater than non-isolated dimmers. The DMX standard allows for up
to 32 receivers per DMX line. The optical input stage of the VX dimmer limits the DMX line to ten
dimmer packs. If additional packs are to be driven from a single DMX line, buffers manufactured
by Leprecon or other suppliers can be used to amplify and distribute the DMX signal.
For more detailed information about DMX 512, see the appendix at the end of this manual.
4.1.2. DMX Indicators and controls
The VX Control card located at the top of the pack contains all electronics needed to decode the
digital DMX signal, and translate that information into signals to control 12 dimmer channels. On
the front panel are the indicators and controls for DMX inputs.
The green LED labeled "signal" is lighted whenever a DMX signal is being received. This indicates
that the controller, cable and DMX input to the VX dimmer system are functional.
The three thumbwheel switches labeled "Start Address" are used to select the board channels
that the VX dimmer will respond to. For instance, a switch setting of 001 will assign VX dimmer
channel 1 to the board control channel 1. Setting the switches to 13 will cause the first VX dimmer
channel to follow board control channel 13. This would be the case when a second 12 channel VX
is used as part of a larger system.
The control electronics is programmed to ignore changes to the address thumbwheels until the
switches have stopped changing. For this reason, it will require a moment for the VX dimmer to
accept a new address after the switches have been changed. This feature is useful when scenes
are stored in the dimmer using a DMX source. For information about storing scenes, see section
5.
The LED labeled "Match" will flash each time a DMX channel equal to the switch setting is
received. For example, if the Start Address switches on the Control drawer are set to 500, and the
console is only outputting 256 DMX channels, the Match LED will not flash, and no dimmer
channels can be turned on.