Blizzard Enclosure User Manual
page 45
Setup and Connections
Operating Mode Setup
Your DEC3 will normally be factory set to the operating mode you specified in your order:
Operating Mode DIP Switch Settings
Mode
DIPswitch Settings
Mode Summary
Standalone
1-6 OFF
Standalone – no DMX/RDM
DMX/RDM
2 ON, 1, 3-6 OFF
DMX/RDM Modes 1-3 – support for remote monitoring
DMX Connections
DMX refers to USITT DMX512, a commonly used control protocol in the entertainment industry,
running over RS485. Consult USITT DMX installation guidelines when laying out a system, or
employ a qualified DMX system integrator.
Note that DMX is optional – in many applications it is not required, and need not be connected.
DMX IN
– Connect incoming DMX to the 2-part 3-pin terminal on the DEC3 control circuit board so
labeled.
Pinout: (1) Ground, (2) Data -, (3) Data +.
DMX THRU
– there are two DMX pass-through terminals – one for a fixture inside the enclosure,
the other to run to the next DMX device in the network. Pinout: same as DMX IN.
DMX Line Terminations
DMX cable runs must be terminated at the far end of the cable run with a termination resistor as
detailed in the DMX standard. This is particularly important for satisfactory operation of DMX/RDM
installations. The individual fixtures installed inside the Tempest enclosures must NOT be
terminated. It is recommended that any line termination is done using the 3-pin terminal
connector fitted to the DEC3 control circuit board.
1.
Make sure that any DMX termination provided by the fixture inside your enclosure(s) is
disabled.
2.
The LAST enclosure in the installed DMX daisy chain should have a DMX Termination
fitted to one of the pass through DMX connectors. Per the ANSI E1.11 standard, the
Terminator shall be 120 ohm +5%/-10% impedance placed between Data+ and Data-. We
recommend minimum power rating of 0.6W for the resistor.
We recommend that the installer fit a label externally to say “DMX Termination fitted
internally”.
Test:
3.
Switch mains power OFF to all enclosures.
4.
Before connecting the DMX line to your controller, measure the impedance between Pin 2
(Data-) and Pin 3(Data+) at the controller end. Reading should be around 100-130 ohms.
