This was taken from an NJD lighting book about the
Data Moon Lighting unit see www.njd.co.uk
The DMX system is a high speed digital data system,
which can transmit all the information required
for light dimmers, multimotor lighting effects, etc.
down a single cable.
It was invented in 1986 for control of dimming
theatre lighting, and has been adapted for the
control of intelligent lighting
Each unit connected to the DMX signal is given an address,
and it compares this to the data being sent on the DMX
cable, so it can determine which data is addressed to it,
It then uses this data to move a motor or set a
brightness level as required by the controller.
As the DMX system can transmit as much information
as 512 analogue control wires down a single cable,
it has to transmit very quickly, in fact,
To make the DMX system work at such high frequencies,
it requires special cable.
DMX cable has a characteristic impedance of 120 ohm.
At the end of the cable or last head unit must have a
terminating resistor fitted of 120 ohm.
Without this, the signal will be reflected off the end of the
cable and damage the new data.
If the cable is not right, the system will not work
or be give wrong instuction,so not doing what you want
to the lighting heads. Good twisted pair screened
cable will work (microphone cable), all joints
must be good and fully screened only use good
jointing boxes or plug and sockets.
Do not use splitters etc. you must go from one head unit
to the next unit ie. controller to first head in put
socket then from the out put socket to the
next head input socket and so on, finishing with the
last head unit with a terminating resistor.
Connecting Data Moon Lighting unit to a DMX controller.
The DMX system has 512 addresses. each address can be
brightness of a single dimmer, or a position of a motor.
The Data Moon controls 2 motors and the lamp:
it requires four DMX addresses, on; three of which
are used,in order to maintain compatibility with the
IQ range, The Data Moon can be programmed to any address
from 1 to 256, so there can be up to 64 channels of
Data Moons on a controller. Any number of Data Moons
can be assigned to the same address then they will
Each Data Moon occupies four DMX channels.
The DMX address of the first channel can
be set to any address then they will form identically.
The switches are labelled 128, 64, 32, 16, 8, 4, 2 and 1
Add up the numbers of the switches that are ON and
then add 1. This number is called the start address.
The dish motor appears at the start address,
start address plus 1 is not used, the colour/gobo
is at the start address plus 2, and black out at the
start address plus 3, (ie. if switches 32 and 8 are ON,
then start address is 32+8+1= 41, the dish motor is
on channel 41 and the colour/gobo on the channel 43,
channel 44 controls the black out).
The DMX dimmer levels control the movement as follows:
dish motor: increasing data gives
clockwise rotation of the beams.
The dish will take the shortest route to the new position,
so that continuous rotation can be achieved.
ie. from 255 to 0 will be one small step clock wise,
not almost a full circle anti clockwise.
DMX level Colour gobo
224 - 255 white circle
192 - 223 blue spiral
160 - 191 red segments
128 - 159 green triangle
96 - `127 pink star
64 - 95 cyan dots
32 - 63 yellow tunnel
0 - 31 magenta squares
The fourth channel controls the black out as follows.
0 Lamp OFF
1 - 223 Normal operation
224 - 255 Black out shutter.
Connectors 1/4 jack plug / socket