The Mobile Disco Knowledgebase

Quick (and easy) guide to DMX

Setting units in Master/Slave link mode

Setting all Dipswitches 1 through to 9 OFF will put the unit in MASTER mode when linking units together, this causes the unit to transmit data to any SLAVES which may be connected. Units are put into SLAVE mode by setting Dipswitch 1 ON and 2 through to 9 in the OFF position.

DMX Address setting

Each of the Dipswitch has an associated weighting, meaning each numbered switch is worth a certain value. This is represented mathematically by the Formula 2^(X-1)=weighting (where X is the number of the switch)

(This ^ symbol indicates that the proceding number is the power to which the number before is raised to. ie 2^2 = 2² = 2x2 = 4 and 2^3=2³ = 2x2x2 = 8)

Example:-

Switch 2 has a waiting of:- 2^(X-1) (Where X is 1 for switch 1)

2^0(*)= 1

* (Anything raised to the power of Zero is 1)

Similiarly Switch 3 has a waiting of:- 2^(3-1) (where X is 3 for switch 3)

2^2= 2x2 = 4

The value of each switch that is set in the ON position accumulates. For the Picture above switches 1-5 are OFF and 6-10 are ON. This is best displayed in a table as shown below.

Dipswitch 1 2 3 4 5 6 7 8 9
Weighting Calculation 2^0 2^1 2^2 2^3 2^4 2^5 2^6 2^7 2^8
Weighting 1 2 4 8 16 32 64 128 256
ON = 1 OFF=0 0 0 0 0 0 1 1 1 1
Values 0 0 0 0 0 32 64 128 256
Total 32+64+128+256 = 480

Therefore a Unit with the Dip-switch configuration as shown in the picture above will begin recieving DMX512 data at channel 480.

It is important to remember that the address set by the Dip-switches is the DMX base address, this means that the unit will start reading data from this address and procede to read remaining channel functions on consecutive addresses.

For instance if a Scan (Requiring 4 DMX channels), dip-switch settings were set as shown in the picture above channel 480 would control its PAN movement, 481 would control its TILT movement, 482 the COLOUR wheel position and 483 the selection of the GOBO.

Hopefully this helps a little

Submitted by Andy Harris - 'Ads Entertainments'

DMX Settings